‘You’ve always been one of my best men, Spider,’ said Hargrove. ‘I know you’re not bent, so I’ve got to ask you, unofficially and off the record without the machine running, is there anything you want to tell me?’

Shepherd stayed silent.

‘Anything at all?’

Shepherd shook his head.

There were two dozen DEA agents working out of the American embassy in Grosvenor Square, but Matt Willis was the one Major Gannon regarded most highly, not least because Willis had spent seven years as a Navy Seal and had seen action in the Gulf and Afghanistan.

The American’s Special Forces background gave the two plenty to argue about whenever they met up, and often led to early morning drinking sessions in the Special Forces Club, behind Harrods in Knightsbridge.

Gannon arranged to meet Willis there at lunchtime, so they would not be tempted to embark on a drinking binge. The club was in an anonymous red-brick mansion block. The brass plaque identifying it had been taken down after 11 September and now passers-by had no idea that some of the most specialised soldiers in the world were inside the building, or that drunken SAS and SBS officers often hurtled down the stairs on metal trays – a makeshift toboggan run.

Gannon signed in and went up to the first-floor bar, all dark wood and leather armchairs. Willis was already sitting in a corner, his back to the wall, nursing a tumbler of whiskey and ice. He stood up, shook hands with Gannon, then slapped him on the back and ordered him a whiskey as the major dropped into an armchair. ‘Busy?’ asked Gannon, placing his case on the floor next to the chair.

‘As ever,’ said Willis. ‘You?’

Gannon pulled a face. ‘Sitting on my arse in the barracks,’ he said.

‘Really?’ said Willis, grinning.

‘The Provos are finished, what’s left of the Republican movement are nutters, pretty much, and Al Qaeda aren’t up to much here. All quiet on the western front.’

‘Pity you missed out on Iraq.’

‘Tell me about it. Three-quarters of the Regiment were there but all I did was babysit the bloody sat-phone.’ He gestured at the case by his side. Wherever he went, Gannon had to take the Almighty with him.

The two men clinked their glasses and drank. ‘Have you got time for lunch?’ asked Gannon. The club’s dining room offered the sort of food that soldiers enjoyed – good solid meals with no-fuss service. Willis shook his head. ‘We’ve got a satellite conference with Langley this afternoon.’

‘It was a lot easier before the spooks got involved in drugs,’ said Gannon.

‘It was the end of the Cold War did it,’ said Willis. ‘Had to find themselves a new role and drugs was the war of choice. Half the undercover operations we run come up against CIA agents. They treat us like we’re the enemy.’

‘Same with the cops and our spooks. Hate the sight of each other, and we end up in the middle.’