The first warrant number in the Metropolitan Police – number one – was issued in 1829 and the first police officer to die in the line of duty was one year later – PC Joseph Grantham, kicked in the head while attempting to arrest a drunken man in Somers Town.

Knocking on for two centuries of our dead.

We thought about Billy.

We remembered him.

It is always cool and dark inside the Crime Museum, and although its prime function is as a teaching aid, when it is deserted, it is a place that seems built for remembering.

We thought about the sacrifice our friend had made for people who would never meet him, and we thought about the dangers that he faced every time he went off to work, we thought about the mother and the woman who loved him.

We thought about ourselves and all the luck we had enjoyed so far.

We had our tea.

Then we went back to work.

And this was the ritual too.

32

‘So how did it work?’ Whitestone asked.

Edie and I stood outside the interview room in West End Central, watching on the CCTV feed. Madam Theresa sat with her elderly lawyer.

‘She’s aged twenty years overnight,’ I said.

‘Then that makes her one hundred and ten,’ Edie said. ‘Someone should have busted her years ago. She’s never going to live long enough to make it to the Old Bailey.’

Madam Theresa’s eyes narrowed at Edie as we walked into the interview room.

‘You could have done very well with me,’ the old woman said. ‘Juicy little thing like you. Petite rousse chaude! Hot little redhead! You could have had a great career on your back.’

Edie leaned against the wall and folded her arms.

‘Until I overdosed on Fentanyl during my tea break,’ Edie said.

Madam Theresa looked from Edie to me and laughed bitterly.

‘I should have seen the pair of you coming,’ she said. ‘Slipping in my dotage. Letting my guard down. Becoming too trusting.’

‘Yes, you’re just an old softy at heart,’ Edie said.

I sat next to Whitestone, staring across the table at Madam Theresa. I did not think she would be dead before she came to trial. If anything, she seemed energised by her arrest, full of rage and poison for those who had put her in this room.

‘It was that little Filipina whore in Chinatown, wasn’t it?’ Madam Theresa said. ‘The things I did for her when she was fresh off the banana boat! And she ratted me out! Turning up her nose at me and then sending me a pair of undercover cops. That little bitch. What does she get in return? I bet you all look the other way in Chinatown, don’t you?’

Whitestone rapped her knuckles on the table.