Lil swatted a playful hand at Edie’s head and thrust the Milk Tray at her nurse.

‘Maria?’

‘No thank you, Mrs Wren,’ Maria said, as she finished making up the bed and helped Lil back under the covers.

‘Salamat po,’ I told her and she nodded, smiling at my Tagalog.

Edie sat on the bed and took her grandmother’s hand.

‘Happy, Nan?’ Edie said.

‘Best place I ever lived, sweetheart,’ Lil said, her mouth full of Orange Truffle.

We drove to New Scotland Yard and went up to the first floor where Sergeant John Caine was waiting for us. There were no visitors to the Crime Museum today.

There is a glass cabinet in Room 101 of New Scotland Yard, a modest display dedicated to police officers who have perished in the line of duty.

OUR MURDERED COLLEAGUES

More than a hundred years of faces. The images of the nineteenth century almost grey with age now. All of them are official portraits but some of the faces are dead serious, as if aware of what violent fate was waiting, and some of them grinning with genuine amusement. There were only men in the older pictures but then, from the middle of the last century the faces of the women officers start to appear. Some faces were still in the flush of youth and some in their middle years. Most of them were unknown to me but I had heard about some of them. A few had been my friends.

DCI Victor Mallory. Age 50. Stabbed.

DI Curtis Gane. Age 29. Died of injuries.

All those dead coppers. They were in plain clothes and in the uniform of the Metropolitan Police, most of them long forgotten but some of them so famous that their deaths had been front-page news.

WPC Yvonne Joyce Fletcher. 17 April 1984. Age 25. Shot.

PC Keith Henry Blakelock. 6 October 1985. Age 40. Stabbed.

Rank. Name. Age. And cause of death.

All those policemen and women, I thought. All those different ways for us to die.

Stabbed. Shot. Run over. Killed by a blow to the head. Rammed by vehicle being pursued. Bludgeoned during arrest.

And yet they were not infinite, these ways to kill us. The same causes of death came round again and again and again, and they were no different now than they were when Queen Victoria was on the throne.

Shot. Stabbed. Run over. Shot. Stabbed. Run over. Kicked in the head. Kicked in the head.

John went to put the kettle on as Edie and I stood by the glass cabinet and stared at all those names, our eyes always coming back to the latest one.

‘He’s in there,’ John said. ‘He’s with the rest of them now.’

‘Thanks, John.’

Trainee Detective Constable William Greene, it said. Age 25. Stabbed.