The map showed a T-junction at the point where he thought he was, not a crossroads. On the far side of the junction a bereft-looking wooden signpost leaned at an angle. It was all very peculiar.

He considered backtracking but decided against it, confident that he was in the right place. The GPS would have confirmed it but this had become a challenge, if a minor one, and he was determined to solve it using map-reading and his instincts rather than electronics. It was Stratton’s belief that people had become too dependent on modern technology and that it would eventually lead to the erosion of basic skills.

He put the engine into gear and drove into the junction to get a better look in all directions. The grid reference he had for the MI16 compound was less than a mile away in an unmarked piece of MoD land. No one at the SBS HQ had been to the place before and so there were no clear directions.

Stratton began to turn the wheel to go left but changed his mind, focusing instead on the unmarked lane that carried on straight ahead. He usually leaned more towards taking the route to discovery if he got the chance. On the other hand, now he had a convenient reason to turn around and go home. Not that anyone would have bought the excuse. A strong residue of doubt about the visit prompted his hesitation. Mike had tried to gloss over it as some kind of meeting of minds but Stratton had not entirely bought into that. Ultimately he didn’t like people questioning his abilities and he would always challenge them. But after a couple of days to reflect on the subject, its importance had started to wane in his mind. It was all down to his level of self-confidence. Stratton rarely doubted his own operational abilities. He felt as if he was still in his prime. When he started to have genuine doubts he would know he was over the hill. By then he would be out of the business anyway. It didn’t mean, though, that direct accusations, especially from those he did not respect, could be levelled at him without provoking a response.

He felt reasonably relaxed about it at that moment but he knew that could change if anyone at MI16 rubbed him up the wrong way.

Stratton accelerated the Jeep across the junction and into the unmarked lane. The tarmac quickly turned to mud. Bushes and saplings encroached from either side. The track soon became so narrow that the Jeep could barely squeeze along it. The thick undergrowth on either side was impenetrable.

A sign warned anyone using the lane that government property was up ahead and trespassers would be prosecuted. It was an encouragement to Stratton to keep going at least. At the top of a short rise the ends of a chain fence were visible at either side of the lane. The gate across the road was open. He carried on through and down a steep dip, then to the crest of another rise where the trees thinned out and the dense scrub gave way. A hut came into view on the edge of the track, a robust metal gate - this time closed - just beyond it.

Stratton half expected to find someone in the hut but there was no sign of life. Just a metal box with a card slot. Stratton dug his military ID card out of a pocket and pushed it into the reader. The card came out seconds later, a green light flashed, accompanied by a gentle beep, and the heavy gate began to open.

He must have found the place. No turning back now. There was an element of adventure to this, at least.

He drove on through and the gate closed behind the Jeep. Up ahead the trees gave way to a wide, unfenced compound. An insignificant-looking place, at least compared with the organisation’s daunting reputation and indeed with what he had been expecting. Enough for him to wonder again if it was the right location.

Everything about the compound looked as though it had been constructed during the last world war. An area the size of a football pitch had been cleared of trees, concrete had been poured and levelled, and a collection of long, narrow prefabricated bungalows had been positioned in neat rows. It must have taken all of a week to construct.

Stratton followed a path of faded white lines that turned abruptly through a gap between two buildings into a square. Parked to one side were half a dozen ordinary-looking modern cars, the only indication of human life somewhere nearby. Stratton drove into an empty slot and turned off his motor.

A sudden silence. Stillness. Refreshing until Stratton realised it was too quiet. He couldn’t even hear any birds. He climbed out of the Jeep and looked around. All the windows in the identical buildings had been either painted over or boarded up. Despite the run-down look of the place there wasn’t a speck of rubbish or debris. Stratton wondered if he had missed a sign that instructed visitors where to go or what to do. Or perhaps the super-duper MI16 organisation was unaware that someone had arrived at their secret facility.

Stratton would have loved to surprise Binning and his pals. That would take the edge off his resentment. Somehow, though, he didn’t think he was going to be that lucky.

A small sign above one of the cabin doors announced rather mutedly ENTRANCE and he headed towards it.

As he was about to open the door he glimpsed part of an odd and until now hidden structure - odd insofar as it looked out of place date-wise. A few steps beyond the edge of the cabin a short steel staircase led to a modern helicopter pad. A fire-foam system circled the entire structure, looking as if it was automated. A concrete block on the far side had what appeared to be large metal sheets sunk at a steep angle into its face. They looked like sliding doors although there were no handles.

Stratton returned to the door with the entrance sign. The handle was shiny and well used. He opened the door to reveal a snug, sterile lobby. The rest of the building was partitioned off, the floor covered in fake tiled linoleum and the ceiling stained by leaks.

A gentle humming sound, like that of distant machinery, filtered in from somewhere. Set into a wall was a bland lift door, a single call button on the frame. Stratton pressed it.

The lift opened to reveal a space big enough for half a dozen people. He stepped inside. The door closed but the lift remained still. There were only two buttons and a card slot on the control panel. He pushed the lower button. Another humming sound came from above but he felt no sense of movement. Either it was an incredibly smooth mechanism, or something else was happening.

A series of stark blue LED lights, their bulbs hitherto invisible, rippled from the lift’s ceiling to the floor.

‘Remove the battery from your communication device, please,’ a softly spoken computer-generated voice instructed.

Stratton took his BlackBerry from its hip holster and as soon as he removed the battery the voice thanked him.

‘Remove your wristwatch, please.’

Stratton frowned and removed his watch. A metal drawer slid out from the side of the lift.

‘Place all items in the drawer, please.’

Stratton obeyed. The drawer closed.

‘Thank you.’

The lift began to descend.

When it came to a halt the doors slid open. Binning stood in front of him dressed in a pair of running shorts and a sleeveless sports shirt with a towel around his neck, looking as if he’d just had a rigorous workout. His muscular arms and legs presented quite the picture of athleticism.

‘Stratton,’ he announced, wearing a broad smile and acting like they were old friends. ‘Good to see you again.’ He held out a hand.

Stratton stifled his hostility and shook the man’s hand. ‘Hi,’ he said, smiling slightly and wondering if Binning was a two-faced sod, thick-skinned, or had had nothing to do with the criticism that he had faced. He chose to believe the first option just in case.

‘Sorry you were left to fend for yourself up there. I was in the middle of a fierce circuit when I heard you’d arrived. Do come in.’

‘This box has my phone and watch,’ Stratton said.

‘Of course.’ Binning pulled a card from a pocket. ‘It’s routine, I’m afraid. It’s designed to detect electronic devices, weapons and explosives. We have no physical security in this place, no guards. Nothing’s allowed in or out without clearance. I’m qualified at least to get you your phone and watch back.’ He slid the card into the slot. A second later the drawer opened and he handed Stratton his items. ‘So. I take it you found us without any problems. I would expect so. Man of your calibre. I see you like an open-top Jeep even in the middle of winter. Man after my own heart.’

Binning was certainly in a chipper mood.

‘I don’t suppose anyone warned you about this place,’ the scientist continued as they stepped into a pristine white pentagon-shaped lobby, the ceiling low, a few chairs around the walls. ‘I don’t know the last time one of your people came up, and I’ve been here six years. Let’s start with the canteen, get a cup of tea, warm you up a bit. Then we’ll meet the boss. I think he’d rather show you around himself.’

Binning led the way into a broad curving corridor. It was a complete contrast to the dilapidated cabins above.

‘How far down do you think we are?’ Binning asked.

‘Haven’t a clue,’ Stratton muttered, uninterested in guessing games.

‘The ceiling is a hundred feet from the surface. There’s supposed to be over three miles of tunnels down here but unless they’ve hidden some of them I think that’s an exaggeration.’

One of the walls gave way to plate glass from floor to ceiling, an empty conference room beyond. Then a series of offices and data-storage rooms either side of the corridor. It was all very high-tech. The place sounded alive, a mixture of electronic humming and moving air.

‘They built these tunnels at the same time as the buildings up top, a couple of years into the Second World War. Then it became some kind of government emergency evacuation centre in the event of a nuclear attack. That was sometime during the late 1940s, early 1950s. MI16 took it over twenty years ago. It has been completely gutted and modernised, of course.’

Binning pushed through a pair of swing doors into a canteen equipped with chairs and tables for a dozen people. The place had a row of food and drink dispensers, a handbasin with a soap dispenser and paper towels, and several hatches labelled for various types of waste that were set into a wall.

‘We’re very much a help-yourself organisation down here. Everything’s self-service. All part of the security. You get used to it,’ Binning said as he pushed a button on a machine that responded by dispensing a plastic cup followed by a jet of brown liquid. ‘Tea, coffee, or something else perhaps? There are sodas, fruit juices, soup if you prefer.’

‘Coffee, thanks. White, no sugar.’

Binning pressed the appropriate button but the machine did not respond. ‘Of course, it’s a bugger when something breaks down. It’s like trying to pass a bill through Parliament to get a mechanic down here.’ The machine suddenly responded. ‘Do you know much about MI16?’ he asked, handing Stratton the drink.

Stratton shrugged. ‘Only that you make toys.’

‘Yes, I do like that expression. War toys for war boys. We’re essentially divided into three parts: research and theory, construction and development, and then testing and field trials. We have around a dozen staff down here, a dozen more low-key techs at another surface location. We work in quite a unique way, a sort of free-form system. Anyone can work on any project at any of the stages - within reason, of course. Can’t neglect the boring jobs or crowd the interesting ones. One of my specialities is simplification. Much of the equipment we produce is far too technical to hand over to you chaps.’

‘We’re a bit thick, I suppose?’ Stratton said, sipping his coffee.

‘I wouldn’t have put it quite that way,’ Binning said, with a grin. ‘You’re soldiers, not scientists. But then again, it’s not always easy or possible to make things user-friendly for everyone. Look how long it took to make the computer compatible with everyday users. We don’t have the facilities, the manpower nor the time for that kind of compliance. Once we’ve built it, we need to get it in the field as soon as we can. Most of the things we put together three years ago are already out of date. A lot of them never even reached the field, at your level, because they were too complicated.’

Stratton found the coffee bitter. ‘So who did?’

‘I beg your pardon?’

‘Who did take them into the field?’

Binning wasn’t expecting the question. ‘I don’t think that’s for me to say, really. Shall we press on?’ He headed back through the door.

Stratton poured the coffee down the sink, placed the cup through the hatch marked ‘plastic rubbish’ and followed the scientist. As they walked, a casually dressed man in his late fifties stepped into the corridor. ‘Hello, Phillips. This is John Stratton from the SBS,’ Binning said.

‘Ah. Right,’ Phillips said, offering a hand while inspecting Stratton through his glasses as if trying to bring him into focus.

Stratton shook it. ‘Hi.’

Binning did not hang around and moved on. Stratton caught him up. The scientist said in a low voice, ‘We’ve got a few old fogies here. Surprisingly youthful team otherwise. That’s all Jervis’s doing. You know Jervis?’

‘Yes.’

‘He takes a lot of interest. Believes technology moves so fast that only younger minds can keep up with it. I’d be inclined to agree but I’m mindful of the fact that it probably means I’ll be turfed out before I think I’m ready.’

They arrived alongside a large room beyond another plate-glass wall. A young woman in a slim-fitting jumpsuit and wearing protective goggles was operating a complex-looking piece of machinery.

Binning stopped to look at her with more than polite interest. ‘Rowena Deboventurer,’ he announced, as if there were a lot more to say about her. He tapped on the glass. She looked around at him, her expression blank as though he wasn’t really there. She glanced at Stratton for less than a second before going back to her work.

‘Whatever your first impression of her is, you’re probably right,’ Binning said, smirking. He walked on. Stratton thought the young woman looked very cute.

Behind yet another glass wall lay a dojo-and-gym combination: on one side of the room was a collection of weights and workout machines, on the other a judo mat. A tall blond-haired man who looked about the same age as Stratton and Binning and was wearing a karategi was conducting a kata, each move focused, strong, crisp and decisive, his arms and legs lashing out in precise arcs at an invisible foe.

Binning watched with interest, nodding in approval occasionally as though acknowledging the accuracy of the strikes. ‘Our intrepid boss. Jason Mansfield. A third dan in karate, brilliant nuclear engineer, and handsome to boot. Quite the perfect male, don’t you think?’

Stratton wondered if Binning seriously expected him to agree. It just wasn’t the sort of thing one bloke said about another where he came from.

‘Rather an extraordinary fellow. Flunked his first degree at Oxford because according to him it was boring and failed to stimulate him. That was when we first met. People put him down even though he was playing with theories that most of them couldn’t fathom. The underprivileged background didn’t help. He did impress some of the professors with his theoretical designs but generally they saw him as a flash in the pan who would amount to little. We all did. Probably what drove him forward. Einstein never completed his first degree either. When Jason left Oxford nearly everyone thought he’d disappeared down some hole in the ground, myself included. But the next time he turned up he shocked all of his contemporaries. It was at CERN, the European nuclear research institute. After a PhD in particle physics he went on to become their youngest senior engineer. That probably means nothing to you but those are the dizzy heights even young geniuses dream about. Two years ago London recruited him to head up this place. Remarkable, don’t you think?’

‘Amazing,’ Stratton said dryly, confirming Binning’s suspicion that it meant little to him.

On the other side of the glass Mansfield came to a controlled finish, feet together, shoulders visibly relaxing. He stood with his eyes closed, slowing his breathing, allowing the tensile energy of his body to release itself. When he came back to normal consciousness he removed a towel from a rail and wiped the perspiration from his forehead. He noticed the audience. His face cracked into a grin and he bid them enter.

Binning pushed the door open. ‘That looked pretty crisp,’ he said. ‘I still think you need to turn your hips out a little more on the second thrust.’

‘Oh, really?’ Jason replied, twisting his body suddenly and swinging the sole of his foot towards Binning. Mansfield’s subordinate stepped to the side, tapping the foot down with practised ease. But Jason countered with his other leg, followed by an arm, striking repeatedly. Binning defended coolly, stepping back, to the sides, always under control. Jason’s final punch stopped a fraction of an inch in front of Binning’s nose, the arm not fully extended. ‘Strike!’ he shouted nevertheless.

‘You’re an animal,’ Binning retorted. ‘I wasn’t ready.’

‘You should always be prepared. Isn’t that right, Stratton? You’re the fighting professional here.’

Stratton forced a polite smile.

The man held out his hand. ‘Jason Mansfield. I’ve heard a lot about you. Even Jervis hints highly of you, and he says nothing about anyone, and when he does it’s never polite. So what do you say? Shouldn’t a man be prepared at all times?’

‘Sounds pretty exhausting to me,’ Stratton said.

Jason saw the funny side. ‘Which is your preferred martial art?’

‘I don’t have one.’

‘You mean, no specific one?’

‘I mean none.’

‘What do you people practise down in Poole? A hybrid, I imagine. Mixture of various techniques. Ju-jitsu?’

Stratton shook his head. ‘No.’

Jason looked unconvinced. ‘Come on. You must do some kind of self-defence. How do you defend against someone coming at you - with a knife, for instance?’ he asked, adding a mocking jab without actually touching Stratton.

‘I’d shoot them.’

Jason grinned. ‘What if you don’t have a gun?’

‘I’d probably run.’

‘Oh. A dry one, he is, Binning. You’ll get on well here.’ Jason looked Stratton in the eye as though examining his very soul for something. ‘Well. Has Binning shown you around?’

‘Not really,’ Binning said, jumping in. ‘Thought we’d meet the boss first.’

‘Let’s head down to my office, then,’ Jason said, rubbing his face and neck with the towel. ‘We’ll sound out one or two things. Then we’ll show you the rest of the place.’

They headed further into the underground complex, reaching a four-way junction. Another glass wall revealed a conference room. Inside, two men were examining a complicated mathematical calculation on a whiteboard that included diagrams of some kind of device.

Jason put his head round the door. ‘How’s it coming?’

‘We’ve broken it down into a couple of options,’ one of the men replied.

‘Okay. Once you’re certain, bring it back into the theory room and we’ll pick those options to bits.’

‘Will do,’ the man said and went back to the board.

They continued along the corridor. ‘How’s that retractor demonstration coming along?’ Mansfield asked Binning, businesslike. ‘We need that to go without any hitches.’

‘We’re all ready apart from the power plant. I’m told it’ll be here at least a couple of days prior.’

‘I need a guarantee on that. I don’t want to see it plugged into a battery box. We must have the right power units. Otherwise it looks bloody amateurish.’

‘Of course.’

At a door, Jason slipped his index finger inside a scan tube by the handle and the locking mechanism gently clicked open. They went into a rectangular open-plan room, the walls lined on three sides by whiteboards and computer monitors. It had been subtly divided, using movable partitions, into small clusters of tables and chairs, a couple of which were occupied by a handful of staff who were sitting in circles discussing something.

‘This is the theory room,’ Jason said in a quieter voice. ‘Each new project has its own stance, its own position in the room, but also in an open forum that allows anyone with an idea they wish to contribute to do so. One person oversees what we call the subject but other than that it’s a free-for-all.’

Stratton looked at the various ‘stances’, the boards and screens containing mathematical data and diagrams. It was all Greek to him.

When he looked back at Jason the MI16 director was watching him, an expression in his eyes like that of a master examining an uncomprehending child. ‘Bit daunting for you, I expect . . . Let’s go to my office,’ he said, gesturing towards a smaller glass-partitioned space at the far end. ‘Take a seat,’ Jason said as they walked into the office. He sat in a comfortable leather chair behind the desk, a large portion of whose surface was a computer screen.

The warmth was beginning to make Stratton feel uncomfortable and he removed his leather jacket before sitting down.

‘We run a pretty loose ship here,’ Jason began. ‘No scheduled meals or work times. It’s up to the individual. We even have nap rooms,’ he said, raising his eyebrows. ‘The emphasis is placed on freedom . . . freedom to think, to express. The primary function is creation. It’s bad enough having to live like rabbits in a warren. So we do our best to compensate with pitiful luxuries and distractions.’

One such distraction caught Jason’s eye as he looked past Stratton.

Rowena was heading towards the office, no longer in the one-piece laboratory suit but in a short skirt that revealed a pair of shapely legs. Her gaze lingered on Jason perhaps a moment too long as she entered the room but her expression was still void of emotion.

‘Rowena. Have you met John Stratton?’ Jason asked.

‘Yes,’ she said, without looking at the guest and taking a seat in the other side of the room. She appeared aloof beyond rudeness as she pulled out a cigarette packet, removed a slender cigarette and lit it.

Jason smiled thinly as she blew a long line of smoke towards him. ‘That describes Rowena to a T. Rude and rebellious. This is a no-smoking establishment. But she’s invaluable, knows it, and so she gets away with everything.’

The young woman ignored everyone. Binning stared at her in private thought. Rowena somehow involved everyone and ignored them at the same time. She seemed to live under a cloud, contemptuous of everything.

‘I asked Rowena to pop in because she’s, well, a part of why you’re here,’ Jason said, looking at Stratton. ‘I can’t help feeling there’s bad feeling between you and us. I’d like to move beyond it. I think there’s been an overreaction to the hull-recording incident. It’s quite acceptable that under such hostile circumstances an operative could forget to arm the self-destruct option—’

‘I didn’t forget to arm it,’ Stratton said, surprised by his own sudden anger. It was a warning that his previous acceptance of the situation was a smokescreen that he’d created in self-defence. Deep down he still felt sensitive about the incident, at least where these people were concerned.

Everyone else in the room felt the sting of Stratton’s glare although they did not appear to be unduly fazed by it.

Jason took a moment to compose his next words. ‘The likelihood of the device failing to self-destruct after it was armed is very low. But obviously nothing is impossible.’

‘Total crap,’ Rowena snapped, looking at Stratton as if he was dirt. ‘I designed the self-destruct system on that device. It’s simple, functional, and the one that I prepared for the operation worked perfectly. And I’m not going to be blamed by this Neanderthal for some fictitious malfunction.’

Stratton got to his feet, barely able to hold on to his anger. ‘I’m not taking any more of this shit.’

‘Oh, grow up,’ Rowena said, taking a pull on her cigarette. ‘If you prima donnas only knew how difficult it is to dumb down designs just so you can use them you wouldn’t be so damned arrogant.’

The other scientists in the theory room outside the office had stopped talking and were looking towards them.

‘Easy,’ Jason said, getting up and walking around the desk as if to get between the pair.

‘I can see what’s going on,’ Stratton said. ‘You eggheads screwed up and as far as you’re concerned my coming here acknowledges that it was my mistake. Fine. You win. I came. Now I’ll go. That recorder didn’t work. You know it. I know it. It’ll be our little secret.’

‘You bloody coward,’ Rowena retorted, standing now. ‘You may have the guts to do the job but not to admit when you screw it up.’

‘Please! Can we stop this?’ Jason had raised his voice to match the volume of theirs and now he moved to the doorway to prevent Stratton from leaving. ‘Let’s all calm down.’ He faced Stratton. ‘There’s no underhandedness going on here. I understand your feelings, both of you,’ he added, glancing round at Rowena. ‘I think I know how difficult it was for you to come here. You’re an operative and, well, I expect that in your eyes we’re nothing more than a bunch of white coats . . . and in the eyes of some of the people here you’re no more than a mindless thug. I’m being perfectly frank because I want to be fully understood. I believe we’re wrong about each other. I would like to see closer cooperation between us than there has been in the past. For our part we need to know more about how you think, react, analyse. That goes for all operatives and for you in particular, Stratton. You have an impressive record when it comes to thinking on your feet, reacting to life-threatening situations, solving problems under pressure. Yet forgive me if I sound insulting, but . . . well, you don’t have a great education. Your IQ is average . . . don’t get me wrong, please: I’m trying not to sound condescending. What I’m saying is, you have something that isn’t easily quantifiable when it comes to IQ or physical tests. I want to know what that something is.’

Rowena rolled her eyes and sat back down. ‘No one ever heard of dumb luck?’ she muttered.

Stratton realised he was grinding his teeth. Yet the woman had disengaged herself from everyone else, seemingly to concentrate on her cigarette.

A beeper sounded at Jason’s hip. He unclipped the device and checked its screen. ‘I would appreciate it if everyone just took a deep breath and settled down,’ he said, moving back behind the desk.

Stratton picked up his coat and headed out of the office.

Jason frowned as he picked up a headset - a greater priority - placed it against his ear and touched the desk screen to activate a connection. ‘This is Jason . . . I understand . . . Yes, of course. That’s what we’re here for.’

He put down the headset as Stratton reached the door. ‘Stratton. I think you’ll want to hear this. That was a call from London.’

Stratton stopped at the word ‘London’. That probably meant the call had nothing to do with this rubbish. He looked at the scientist.

‘Somebody hijacked an oil platform in the North Sea early this morning. They’re holding some hundred and sixty-plus workers to ransom. An SBS team is on its way here to pick up the G43.’

‘When will they be here?’ Binning asked.

‘They’re in the air. Any time.’

‘Is that all they need?’ Now Binning was completely methodical - his job was to liaise with outside units who needed equipment.

‘That’s all they’ve asked for. But stand by for updates.’

Stratton released the door handle. He wasn’t sure how the news directly affected him but felt he should stick around and see what developed . . . as long as that bloody bitch Rowena kept away from him.

A gentle yet persistent buzz filled the air and a small light flashed above one of the flatscreens on the office wall. Jason used a remote to turn it on. Several split-screens displayed various parts of the compound as seen through a collection of closed-circuit television cameras. He selected one of the views, enlarging it to fill the screen. The camera moved skyward where it picked up a helicopter.

Stratton looked at the screen. It was an SBS Chinook, unmistakable, like a thick, short sausage with rotors on either end. A letter and a pair of numbers flashed on the screen and moved to a corner where they continued to blink.

A voice crackled over speakers. ‘India one-six, this is Whisky four-zero, clearance code Golf two-zero.’

The code the pilot had given matched the one on the screen.

‘India one-six affirmative. You’re clear to land,’ Jason said.

‘Roger that. Thirty seconds.’

Stratton suspected that Chaz and the standby team were on board, probably acting as the advanced recce team preparing surveillance for an assault team, whenever the lads could get back from Afghanistan. He wondered why he had not received a call from SBS HQ. The visit to MI16 was not a priority of any kind. They’d certainly known about this hijacking before he had arrived. Maybe Mike had been serious and they were resting him.

He put the thoughts aside as the powerful helicopter closed in on the landing pad.

Rowena glanced at the screen as if she was only half interested.

‘They’ll no doubt be in a hurry,’ Jason said. ‘Better get down to the airlock and meet them as they clear.’

‘You coming, Rowena?’ Binning asked as he started out of the door.

‘If there’s anything you can’t handle give me a shout.’ She seemed pissed off with him too.

Binning chose not to make the half-expected answer and put her from his mind as he went out.

The helicopter settled onto the pad and the cabin door opened. Men in black one-piece fireproof suits climbed out. Stratton recognised Chaz.

The heavy angled sheets of steel that Stratton had seen began to slide open. A red light to the side flashed and a sign lit up stating ‘ENTER THIS WAY’. The six men filed through the opening while the pilots and the crewman remained on board the Chinook. As the last man passed through the heavy steel door it began to close.

‘I take it you know these men?’ Jason asked.

Stratton was not ready to act as if all that had been said before had been forgotten.

‘Shall we go down and greet them?’ Jason asked. He walked off through the room. Rowena hadn’t moved so, rather than remain with her, Stratton set off after Mansfield. It would be a relief to meet Chaz and the boys.

They headed along another gently curving corridor and soon arrived at a more dingy part of the complex. The concrete was unfinished, as if the construction budget had been exhausted. Exposed pipes and conduits ran across the ceilings, connecting the bare strip lighting.

They passed under an archway into an expansive room containing a cloudy standard-sized swimming pool. Their feet echoed in the cavernous space as they walked along its length. ‘Testing pool,’ Jason pointed out as if he was a tour guide.

Another steel door led through to a wide room where overlapping sheets of rubber hung from ceiling to floor, which was covered in gravel. Around the room were distributed a dining table and chairs, a torn cord sofa, and two ragged armchairs - the cheap furnishings of an ordinary living room. Three men stood around the space in civilian clothes, two standing, one crouching. They didn’t move. Sponge dummies.

Stratton noticed ammunition casings in the gravel as he crunched through it, bullet holes in the furniture. He was surprised. MI16 had a killing house.

Jason glanced back at him. ‘When I got here it was a weapons-testing room. But I decided to make it more entertaining.’ They went into what appeared to be a storeroom containing rows of metal racks and shelving stacked with a variety of mechanical and electronic parts.

A muted alarm began to sound. Jason stopped in his tracks and looked up at the red light flashing above a door at the end of the room. ‘What the hell . . .’ he muttered. He pushed through the door into a dull concrete bunker where Binning stood in front of a control panel, holding a phone to his ear. Above the panel was a small monitor filled with Chaz’s irate face.

‘You were told that all weapons and communications devices were to be left on the helicopter,’ Binning said into the phone, sounding vexed. ‘And under no circumstances were any pyrotechnics to be brought into the complex.’ Binning looked at Jason and shook his head in frustration. ‘One of the bloody fools brought something in. The vault has locked down.’

‘We didn’t bring anything in!’ Chaz shouted in defence of himself and the others.

‘Did you clean your equipment after your last training session or operational task?’ Binning asked. ‘I’ll answer that for you. No. You didn’t. You were warned that the system picks up the slightest chemical residue. If it has anything to do with explosives it reacts. You were told.’

Jason looked around at Stratton with an irritated glare. ‘Don’t these people pay attention to detail, damn it!’

Stratton didn’t like his tone but let it go. The boffins were clearly under stress. ‘What’s the problem?’

‘The security scanning system in the airlock is like the one you went through in the elevator,’ Jason explained.

‘And I put my phone and watch in a drawer and continued on down.’

‘You weren’t carrying any form of explosives. Without the clearance codes access goes into lock-down.’

‘Then give them the code.’

‘We don’t provide them,’ Binning said. ‘London does.’

‘Then send them back up to clear their gear,’ Stratton suggested, looking between the two men.

Jason sighed heavily as he tried to calm himself. ‘We can’t.’

Binning explained. ‘An unauthorised pyrotechnic invokes a Priority One protocol. It’s classed as an SSB, a serious security breach. We can’t override the system response and send them back up to the helipad. And neither can they carry on down to us.’

‘Our security is automated,’ Jason expanded. ‘Designed for a complex without physical security. We have no armed guards. Therefore we have far more stringent precautions . . . Your men are locked in, and that’s that.’

Stratton was getting the picture. ‘For how long?’

‘The vault can’t be opened for twenty-four hours.’ Jason was not apologetic.

Stratton automatically ran through the obvious implications.

Jason got the impression from his expression that it was the fault of MI16. ‘This has never happened before.’

‘Can I speak to him?’ Stratton asked.

Binning flicked a switch on the panel. ‘Go ahead.’

‘Chaz? This is Stratton.’

‘Stratton, what the hell is going on? They said we’re stuck in here for twenty-four bleeding hours.’

‘That seems to be the story, mate.’

‘That’s madness. We’ve got to get on.’

‘I know. There doesn’t seem to be a solution,’ Stratton said, looking at Jason to be sure.

A buzzer went off on the panel. Binning touched a button. ‘Binning here.’

‘London’s just called.’ It was Rowena. ‘The crisis response centre received an airlock-shutdown alarm.’

‘Tell them it’s under control.’ Jason cut in. ‘Give them our duress code, let them know we’re fine. It was an error. The SBS lads brought something into the lock.’

‘What a surprise,’ Rowena said.

‘Have London send the unlock code,’ Jason ordered.

‘We didn’t bring anything into the bloody access!’ Chaz shouted.

Jason looked at Stratton as if he’d been through that already. ‘It will take twenty-four hours to get them out. Nothing can change that.’

‘That’s bloody ridiculous,’ Chaz’s voice boomed.

‘You have to understand what this system was designed for,’ Binning explained. ‘Think of it like a bank vault that someone has tried to rob . . . the Bank of England, for instance. There are billions of pounds’ worth of systems in here. But it’s not just their financial value. Some of the devices would be extremely dangerous in the wrong hands. It would be catastrophic, in fact. There are foreign governments that would give almost anything to get hold of some of the items we have in here.’

‘Yeah, but—’ Chaz began to argue.

Jason was growing more irritated and cut him off. ‘Let me put it another way. If this had been an actual break-in attempt, on a scale of importance to this country’s security your oil-platform hijack would have equated to a handbag snatch in comparison . . . There’s nothing more we can do. Deal with it. Good day to you.’ He headed out of the room.

Binning gave Stratton a sympathetic look and followed his boss.

Stratton watched them go before looking back at the small screen. ‘Sounds like you’re going to have to sit this out for the next twenty-four, Chaz.’

‘That’s just friggin’ brilliant!’ Chaz shouted. ‘We didn’t bring anything in here. Their system screwed up!’

‘I know exactly how you feel. What was the task?’

‘Dropping in some new surveillance device that these guys put together.’

‘When are the assault teams supposed to be getting in?’

‘First packet in the next forty-eight hours. Two more to follow soon after.’

‘Where’s the forward mounting base?’

‘Aberdeen initially. Then on board one of the assault ships. They’re going to give us our RV within the hour.’

‘Any task timings?’

‘No. But they want to have the ability to assault asap. This puts us back big time. Someone’s going to be pissed off in Poole.’

‘I’d better let them know the bad news,’ Stratton said as he realised what he was going to have to do.

‘Sorry, mate.’

Stratton suspected that Chaz was going to get it in the neck. ‘Make yourselves comfortable. I’ll talk to you later.’

Chaz’s frustrated look filled the small screen.

Stratton headed back to the main complex.