‘Funny thing is,’ he said, ‘that when you get dumped on your arse, they tend to get bigger and stronger every time you tell the story. You want us to drive you to an A&E?’

I shook my head.

‘Nothing broken,’ I said, and they both gave me their cocky Scotland Yard grins.

*  *  *

The press were waiting for me when I arrived at West End Central in the morning.

They were milling around and sucking down caffeine under the big blue lamp that hangs above the entrance to 27 Savile Row, young journalists and older photographers, maybe twenty of them, sent out to collect whatever scraps they could on the story that was dominating the rolling news. They stirred at the sight of me. I recognised Scarlet Bush but I did not stop walking. They all crowded in with their little digital microphones and their cameras and their questions.

‘DC Wolfe? Scarlet Bush, Daily Post. Is it true that you were assaulted when you found the body of Darren Donovan? What’s that mark around your throat, Max? Did the Hanging Club do that to you?’

They followed me inside. A uniformed sergeant, red-faced with irritation, stepped out from behind his desk and began shooing them back. The questions became nastier when they knew I wasn’t going to answer them.

‘Is the Hanging Club doing a better job than the police at cleaning the streets, Max?’

‘How does it feel to be hunting heroes?’

‘What about the victims? Do you ever think about them?’

‘Did you see one of them, Max? Did you see one of the Hanging Club?’

No, I thought. But I know a man who did.

In a quiet corner of MIR-1, Professor Adrian Hitchens sat working with a police sketch artist.

‘No, no . . . those eyes are wrong . . . can you erase that and try again? Could we possibly have another go at the mouth?’

It’s never easy. Anyone who sits down with a police sketch artist has been a witness to a serious crime. They are attempting to recall a face that they saw for only moments, usually during a criminal act that was accompanied by extreme violence. In the case of our history man, he was attempting to remember the face of someone who had come barrelling out of a culvert without warning and knocked him flat on his ample backside.

I nodded to the police sketch artist, a woman around thirty who looked as though she had the patience of a Zen monk. She had probably grown up wanting to be the next Picasso or Edward Hopper.

‘How’s it going?’

She showed me her sketchpad with a half-smile. She had drawn the outline of a large oval-shaped head with a sizeable nose in the middle and a pair of ears stuck to the side. And that was it. I looked at Hitchens.

‘So we’re looking for Mr Potato Head?’ I said.