‘I have enough provisions down here to last me a month,’ said Miles. ‘I even have my own swimming pool.’

A green light began to flash on his desk, even before Booth Watson could reply. ‘Daily rehearsal over. We can now return to civilization and have some lunch.’

‘But your staff …’ began Booth Watson.

‘Only Collins is ever allowed to enter my study,’ said Miles, as they walked back up the stairs, ‘and even he doesn’t know the security code.’ He entered the safe’s code which opened the first of the two heavy iron doors. When it swung open, he stepped back inside and waited for Booth Watson to join him, before he pulled the door shut. Once again they were plunged into darkness. Miles tapped his watch, entered eight new numbers, and the door that led back into his study swung open. Miles smiled when he saw the butler waiting for them, with two glasses of champagne on a silver tray.

‘Luncheon is served, sir.’

• • •

Lamont didn’t even attempt to shadow DI Ross Hogan, as he knew he would be noticed within moments by the sharpest undercover officer in the business. He satisfied himself with finding a spot where he wouldn’t be seen, while he waited patiently for his quarry to appear.

As usual, Ross left Josephine Colbert’s flat at around seven thirty. He was wearing a freshly ironed shirt and a silk tie, so Lamont knew he wasn’t going home, but straight to the Yard.

Josephine Colbert appeared a few minutes after ten. She was dressed in a designer tracksuit and set off on her morning jog. She returned about thirty minutes later, and didn’t appear again before lunch.

Her afternoon consisted of shopping, the florist, the grocer, the hairdresser, and the occasional visit with a girlfriend to a French cinema in Chelsea. Lamont had never once seen her with another man, other than when she attended her weekly meeting with Mr Booth Watson at No. 5 Fetter Chambers.

His final task was to hang about inside the entrance of the Army and Navy Stores on Victoria Street until Hogan left the Yard at the end of the day. If he turned right, he was taking the tube home; left, and he would be hopping on a bus bound for Chelsea. The trips to Chelsea had become more and more frequent.

Tonight, he turned right, so Lamont assumed he must be going home. However, to his surprise, Hogan walked straight past the entrance to the tube station and continued on walking. Aware that he couldn’t risk following him, Lamont decided to head home, but changed his mind when he saw Hogan enter a shop. He took a closer look at the sign above the door – H. Samuel and Company, Jewellers. He stepped back into the shadow of a doorway until Ross reappeared twenty minutes later carrying a small bag, and headed back to St. James’s station, where he disappeared underground.

Lamont walked quickly across to the jeweller’s shop. He marched in to find a young man taking some necklaces out of the window in preparation for closing for the night. Lamont showed him his old warrant card, a thumb covering the expiry date.