The three bikes sped away, heading south. The three riders were experienced and they cut through the traffic like sharks through a shoal of fish. They had a well-practised technique for getting through red lights. The lead bike would hold up the traffic that had the right of way while the bike with Shepherd sped through, then the third bike would move to the front ready to deal with the next set of lights. The riders were so efficient that at no point did Shepherd’s bike drop below thirty miles an hour, and for most of the time they were travelling well above the legal speed limits, sirens wailing and lights flashing.

They were soon driving through Bromley, and the traffic was lighter so they picked up speed.

‘Spider, they’ve just passed Junction Seven,’ said Button. ‘We’re looking at you on the map and I don’t see that Junction Six is going to work so we’ll stick with the original plan and get you on at Junction Five.’

‘Roger that,’ said Shepherd.

‘We have two traffic cars behind the truck, one has eyeball on the vehicle and they’re expecting you,’ said Button.

The three bikes sped south along the A21 and then turned on to the A224. As they approached Junction 5 Shepherd called up Button. ‘Just about to join the M25,’ he said. ‘Where are they?’

‘Five minutes away,’ she said. ‘The traffic is thinner now and they’re moving at about thirty miles per hour. Best you hang back and we’ll see what they do.’

The riders were all tuned in to Button’s frequency and they pulled in to the side of the road. Five minutes later she came back to say that the truck had passed Junction 5 and was still on the M25.

Shepherd’s rider nodded at his two companions. From now on they would be travelling alone and without sirens and lights. The single bike sped off down the approach ramp and joined the motorway traffic. They kept on the hard shoulder until Shepherd saw the traffic car ahead of them. The rider had also seen the police car and he accelerated to bring them alongside. There were two officers in the vehicle. The passenger looked across at them and Shepherd motioned for them to pull in on the hard shoulder.

As soon as the car had stopped Shepherd handed his helmet to the rider and climbed off. He flashed the rider a thumbs-up and got into the back of the patrol car. ‘Hi, guys,’ he said. He pointed ahead. ‘Follow that truck.’

The car edged into the traffic again, and then moved smoothly into the middle lane. Shepherd took out the Glock and checked the action. ‘I’m Dan,’ he said.

‘Alistair,’ said the driver. He was grey-haired and in his early fifties, probably close to retirement. ‘Pleasure to have you on board.’ He seemed totally unfazed by what was going on.