Bolt knew that his boss was always on the lookout for the big result that would get him on to the next rung of the SOCA ladder, and nearer to his final goal of directorship. Ordinarily, Bolt would have let it go. He was used to Barry's attitude, and because he was a decent enough boss he could generally tolerate it, but these weren't ordinary times. 'I'll be happy when we get Tina and Jenny Brakspear back,' he countered, making little attempt to disguise the irritation in his voice.

'Of course, of course,' said Big Barry, backtracking. 'And what about Roy Brakspear? You said he was at home yesterday morning. Is it possible he's still there?'

'I doubt it, sir. My gut feeling is that Hook would have moved him after Fallon turned up, just in case Fallon raised the alarm. And if not then, they'd have moved him by now because Hook must know we've spoken to Fallon.'

'Hook's got a lot on his plate at the moment and he can't be operating with that many people. He might not have had the chance. Can you get down to Brakspear's place and take a look around? You're up that way, aren't you? In the meantime, I'll get a full surveillance team with armed back-up, and a search warrant sorted out. We might have to break him out of there.'

'I don't want to do anything that endangers Tina, sir. Or Jenny.'

'We'll do what we can to bring them home in one piece, but I'm sorry to have to say it, old mate, but as of now they've ceased to be top priority.'

Bolt and Mo were exhausted, operating purely on adrenalin as they drove to Brakspear's place.

'I want to tell Saira to take the kids out of London for a couple of days,' said Mo after a long silence. 'Her sister's in Leicester. They can go and stay there. There's enough room.'

'Don't do anything yet,' Bolt told him. 'We don't even know the current whereabouts of the gas, and it's important we keep things under wraps as much as possible. We don't want to start some kind of panic.'

'That's easy for you to say,' Mo snapped. 'You don't have a family.' He stopped himself from going on, a look of anguish crossing his face. 'I'm sorry, boss, I didn't mean it like that. It's just, you know…' He shook his head. 'All this is a lot to take on board.'

'It's all right,' said Bolt. He knew he'd almost certainly have done the same if Mikaela was still alive: made a call, told her to keep quiet but to get out of the city. Now that he lived alone it was hypocritical for him to deny others the chance to put the safety of the people they loved first. 'Do what you think's right, Mo,' he said eventually. 'I won't stand in your way.'

Mo nodded, and fell silent again.

It had just turned quarter to five when they reached Roy Brakspear's house. Bolt slowed down a touch as they passed the front entrance. The wrought-iron gates were shut but he caught a glimpse of Brakspear's car on the driveway.

They parked next to a terrace of whitewashed cottages nearby and got out of the car. The first signs of light were appearing on the horizon and the early morning was peaceful and silent. Big Barry had called back to tell Bolt that a surveillance team wouldn't be available for at least an hour, but he'd also said that if he thought the place was empty then they should go inside and worry about the consequences later. Which suited Bolt just fine.

A footpath at the end of the terrace ran parallel to the exterior wall of Brakspear's property to a cornfield beyond, and they moved up it in silence. The side gate was locked, but as long-term surveillance officers they were used to getting into places they weren't supposed to, and they helped each other over the wall and into the garden.

The house was quiet, with all the curtains drawn, and they crept quietly across the lawn until they reached the back door. Bolt listened at the glass but heard nothing beyond. He tried the door handle but it was locked. The lock was old, though, and could be picked in seconds.

He and Mo exchanged glances. It was likely Brakspear wasn't there, but it was also possible he was, and that whoever was baby-sitting him would be armed.

'Let's do it,' whispered Mo.

Bolt nodded, produced his picks, and a few seconds later they were inside an old-fashioned utility room with a washing machine and fridge freezer. Both men produced their standard-issue pepper sprays – the only weapons they had, and woefully inadequate if they encountered trouble. Holding his out in front of him, his finger on the nozzle, Bolt crept through the silent house, conscious of Mo right behind him.

The utility room gave way to a spacious kitchen with a breakfast bar in the middle that had obviously been refitted recently. Unwashed pots and pans filled the sink and there was a faint odour of fried food.

They moved into the silent gloom of the hallway. A dying moonlight filtered in through the window above the front door illuminating a framed poster-sized photograph on the opposite wall. Bolt stopped and inspected it.

The photo was a family shot of a younger Roy Brakspear standing between an attractive woman in her thirties and a cute-looking girl of about ten, which must have been Jenny. All of them were smiling at the camera, and even in the gloom Bolt could see that Brakspear looked genuinely happy. A man with his family. The photograph resonated with Bolt. It also angered him because it demonstrated so perfectly the casual evil of the men who were putting him through this. Bastards. A sudden desire for vengeance ripped through him, so intense that it made him shiver.

He turned away and padded silently across the hallway to the staircase.

That was when he caught a faint stale smell coming from upstairs. Like rancid meat.

He stopped, turned. Mo had caught it, too. He was wrinkling his nose. They both knew what it meant.

Bolt headed up the stairs and out on to the landing. The door opposite was shut, but the smell here was much stronger and hung heavy in the air. The murky silence seemed loud in Bolt's ears.

Holding the pepper spray in front of him, he slowly opened the door and stepped inside.

Roy Brakspear was lying face down on the bed, sideways on, his legs dangling off the edge. He was wearing casual middle-aged clothes – a pair of slacks and a navy sweater – tan brogues on the feet. His arms were outstretched on either side of him where he'd fallen and a small pool of blood had formed round his head. Further drops speckled the sheets where the bullet that had been callously fired into the back of his head had exited.

Mo came in and stood beside Bolt. He didn't speak.

'Poor sod was just a loose end to them,' said Bolt, looking down at the body. He thought about the smiling husband and father in the downstairs photo. Two of that family were now dead. It was possible the third member, Jenny, was too, and if she wasn't yet she would be once the mustard gas was in Hook's hands.

They searched the rest of the house, throwing all the lights on, no longer needing to keep quiet, but there was no obvious evidence pointing to either the identity or the location of the kidnappers. The place would have to be searched a lot more thoroughly but this would now be done by scene-of-crime officers.

They left the way they'd come in, and Bolt put a call in to Big Barry. 'Bad news,' he said when his boss answered, and he told him what they'd found.

'Poor bugger,' sighed Barry with only the barest modicum of sympathy. 'I've got news for you as well. There's good and there's bad.'

'What's the good?'

'Your hunch paid off. We checked Brakspear's phone records, got the number for the drivers' agency he used, and we've finally got the name of the driver picking up the load, and the registration of his lorry.'

'What's the bad?' asked Bolt, even though he could guess what it was.