They arrived in Welbeck Street to find that Treslake had a team of six watchers and four armed police officers.

‘Tindall’s flat is on the third floor, sir. I’ve placed two men on the landing above and one on the landing below. The rear of the flat opens onto a deep courtyard between this block and the one behind it. I’ve got one man in there. There’s no question both men are in the flat. We can either wait until they come out, or go in: it’s your decision, sir, obviously.’

‘Obviously, Treslake. We’ll go in now; we could even catch them transmitting. Webster, you wait here; Treslake, keep your watchers where they are, and you and the police come with me – you too, Hendrie.’

It was clear to Hendrie that seven men climbing the stairs and moving along the small corridor outside Tindall’s flat were bound to make a noise, however much they endeavoured to avoid it. Treslake rang the doorbell and it was a full minute before Tindall’s muffled voice could be heard from inside the flat.

‘Who is it?’

Treslake explained that he had a parcel, but there was no response. One of the policemen pointed to a spyglass set high in the door and off centre. It was obviously not meant to be seen. Gilbey nodded and Treslake barged at the door.

‘It’s solid, sir, reinforced. We’ll need the hammer.’

It was another minute before they managed to break in. Hendrie was the last to enter, and as he did so, he spotted an open window in the lounge and heard the sound of shouting below it.

‘Stay where you are – don’t move.’

‘Don’t be a fool, Tindall, for Christ’s sake.’

‘Treslake, you need to do something…’

‘Llewellyn, perhaps this can be…’

Llewellyn Tindall was standing in the bedroom with his back to a large mirror, the bed in a state of disarray next to him, facing the open doorway. His dressing gown was only loosely done up and he was naked underneath. In his hand, which was shaking violently, was a Webley service pistol, its barrel bouncing around like a conductor’s baton. At first he pointed it at the ceiling, then held it down as if he were about to drop it; then he wedged it under his jaw before lifting it up and holding it against his temple.

‘Come on, Tindall,’ said Gilbey, adopting an almost avuncular tone. ‘You’re not in any kind of trouble.’

Tindall stared at him in utter confusion: there was no doubt he was in all kinds of trouble. Then, before anyone could move, he pulled the trigger.