'I don't think I did-'

'And there aren't many good ones around, are there? So I'm thinking that it's only a matter of time before the authorities come knocking at your door.'

'Shit, Michael. You know me. I'm no tout. I've never informed on anyone in my life. I'd never tell the Brits a thing, and they're not going to find me anyway.'

'You said yourself, Eamon, there'll be hundreds, possibly thousands, dead. The pressure for a result's going to be enormous. They'll find you, and when they do, they'll be looking for me.'

There was a pause of several seconds and then, working hard to keep his nerves in check, Donald smiled grimly. 'I thought you might try something like this, Michael. So, I got myself a little insurance.' He raised his hand to reveal a mobile phone in the palm. 'If I press Send, this phone will transmit an electronic signal to the battery pack in the lorry, and it'll detonate the bomb immediately.' He stroked the button with his forefinger. 'Even if you put a bullet in me, it'll make no difference. My reflexes will set it off anyway, and your whole op will have fucked up.'

Hook's expression darkened. 'You're bluffing.'

Donald shook his head, relieved to see he'd caught the other man out. 'No, Michael, I'm not. Now, what I'm going to do is back out of this building, make my way to my car, and drive away. If nothing happens to me en route, I'll chuck this mobile and the bomb will go off as planned. But I'll be keeping my hand on this Send button the whole time, and if you try anything – anything at all – then, kaboom: the only casualties of this whole job are going to be a few sheep, and maybe an unlucky farmer.' He backed away slowly towards the barn doors, keeping his eyes fixed on the other man. 'You understand what I'm saying?'

'All right, go,' said Hook, his eyes cold. 'No hard feelings, eh? It's just business.'

'Sure,' said Donald, ignoring the hammering in his chest and the sweat running down his face. His free hand found the door handle and he squeezed it tightly, knowing he was only a few seconds away from safety, feeling confident enough to say, 'I still want the balance of my money, though, Michael. I did my job. You owe me.'

Hook opened his mouth to reply, but any words he might have spoken were drowned out by the voice that came through loud and clear from a megaphone outside, accompanied by the heavy beams of mounted flashlights as they were simultaneously switched on, illuminating the barn's interior.

'Armed police. You are surrounded. Come out with your hands up.'

'Jesus!' Terrified, Donald swung round. And in doing so he made a single, fatal mistake because he took his eye off Hook, and as he turned back round, the pistol kicked in the other man's hand.

Donald felt a searing pain in his wrist, and the mobile he was holding clattered uselessly to the floor. He tottered unsteadily on his feet, before leaning back against the door for support, clutching the wound with his good hand.

Hook watched him calmly, his unnatural face almost serene in the fixed glow of the police flashlights and Donald was amazed that he seemed so unperturbed. You had to hand it to the bastard. He knew how to stay cool under pressure. Donald could almost have admired his poise if it wasn't for the fact that his one-time colleague was about to kill him.

Their eyes met, and Donald's expression hardened as he accepted the inevitable. 'You treacherous fucking freak,' he hissed through gritted teeth, determined not to show his fear in these last moments.

'Perhaps,' said Hook evenly, and pulled the trigger.

It was hard to believe she was still alive, but then, thought Mike Bolt with a burst of exhilaration, Tina Boyd had always been a survivor. It was one of the things that made her so attractive.

But although Mo was already on the phone to HQ organizing a trace on the mobile she'd called from, which given modern technology and the resources involved should take only a matter of minutes, they still didn't know exactly where she was. Bolt was sure she'd still be at Willow End Farm, although why Hook was keeping her alive was anyone's guess. The GPS on the dashboard gave an ETA of four minutes, but with the speeds Bolt was doing he was certain he could make it in three. It was raining now, and getting harder to see, and he had to use all his concentration to keep the car from losing control on the winding country roads. He'd already had one crash this week. Another one and he'd probably be suspended from driving on duty for months.

He slowed down as he came to a blind bend.

'They should have a trace on the phone in the next five minutes,' said Mo, steadying himself against the dashboard, 'and Essex police have just arrived on site and are securing the area, so no one's going out.'

'Shit!' yelled Bolt, slamming on the brakes as he came round the bend, almost blinded by a set of approaching headlights on full beam that had suddenly appeared in the gloom.

The lorry was weaving all over the place as it came towards him far too fast and Bolt had to swerve violently to avoid it, skidding through the wet and only just managing to stay on the road. He screeched to a halt and, looking in his rearview mirror, saw the driver do a poor job of manoeuvring his vehicle round the final curve of the bend. He noticed that it was white and large.

Unusual for a vehicle that size to be out on a road as quiet as this.

'It looks like our lorry,' said Bolt, doing a rapid three-point turn. 'I thought they were meant to have secured the area.'

'Surely we're not going to follow it?' asked Mo as Bolt accelerated off in pursuit. 'We don't know who's driving that thing, boss. It could be some kind of suicide bomber.'

'I want to get close enough to show it we're police. If the driver's one of the bad guys he's not going to want to stop, so we'll call for back-up.' Mo looked scared, and Bolt was too, but he was also excited. 'I'll stay well enough back so that if he tries anything we can abort without getting blown to pieces.' He glanced at Mo's stricken face. 'I won't do anything stupid, I promise.'

Within the space of a few seconds they'd closed in on the lorry, and with the car ten yards back from it Bolt pulled into the middle of the road. Just in case the driver had somehow missed the flashing blue light in his wing mirror, he began flashing the car headlights in rapid succession.

If he was innocent, the driver would stop.

He didn't. Instead he accelerated, weaving down the road, taking the next corner too fast, the wet road slicking beneath his wheels.

'Get on to HQ now,' Bolt said, gritting his teeth, pulling back a little as the full enormity of what he was doing came home to him. 'That's our gas.'

Mo was back on the line in seconds, putting the phone on loudspeaker and shouting out their location and current direction, using the GPS for guidance.

A few seconds later the voice of DAC Bridges came down the line, strained with the tension he must have been feeling. 'We're sending in back-up and helicopters. Keep well back but do not lose it. I repeat: do not lose it.'

The lorry braked suddenly. Bolt braked too, harder, going into a skid, suddenly only five yards from the back of the vehicle, and the gas.

The lorry accelerated again, now on a straight stretch of tree-lined road.

Bolt fought the skid, managed to straighten up, and put his foot down. The Jag's speedometer showed fifty, and the lorry was beginning to pull away from him.

'Jesus,' hissed Bolt. 'He's going way too fast.'

'We have local police setting up a roadblock at the junction of the B1057 and the 184,' said Bridges.

'Then they've got about a minute to do it,' Bolt told him, glancing at the GPS, 'because we're less than a mile short of it and this guy's driving like a maniac.'