Harry sat down in the chair opposite Kerridge. ‘So it looks as if someone hired him to kill Lady Rose?’

‘That’s just the way it looks to me,’ said Kerridge gloomily. ‘This gets worse and worse. He had a lady’s purse pistol on him. I’m sure it’ll turn out to be the one that was used. Blast!’

‘Did this Reg have any visitors when he was in prison?’

‘Wasn’t allowed any. If his wife had still been alive or if he’d had any children, then the authorities would have allowed them to visit, but no one else got in.’

‘May I talk to this screw myself?’ In Pentonville Prison in 1840, prisoners were supposed to turn a crank on a machine. If the prisoner was to be punished further, the screw was tightened, and so that was how prison warders came to be known as screws.

‘I’ll give you a note. His name is Henry Barker.’

Giving Becket the rare treat of taking the wheel of his new motor, Harry went to Wormwood Scrubs. He saw the governor and gave him Kerridge’s note, and Henry Barker was summoned.

‘I have Detective Superintendent Kerridge’s permission to interview you,’ said Harry. ‘I am Captain Cathcart.’

‘I’ve heard about you,’ said Barker. ‘Private detective, ain’t you?’

‘That is correct. Now, what sort of character was this Reg Bolton?’

‘Brutal. He terrified a lot of the prisoners.’

‘Did he say anything to you, anything that might give us a hint that someone might be paying him?’

‘Well, these hardened criminals always like to brag, Captain. The day afore he was leaving, he was grinning all over his face.

‘“One more day to go,” I says. He says, “I ain’t coming back here no more,” he says. “Good,” says I. “Mending your ways?” He grins and says to me, “I’m going to be a gent. I got connections. Got a good job waiting for me.”’

‘And what did you gather from that?’

‘Villains never change. I thought maybe one of the other villains had put him in touch with a gang.’

‘Did he have a particular friend?’

The warder shook his head. ‘The others detested him, even the real hard ones. He was a nasty bit of work. I mean, I’m only guessing one of them offered him a job. But I never saw him talking much to anyone all the time he was here.’

‘How long was he in here for?’

‘Two years.’

‘And no one visited him during all that time?’

‘No, sir. Not a one.’

Harry turned to the governor. ‘Would it be possible to find me his home address?’

‘I’ll get my secretary to look up the records,’ said the governor. ‘Thank you, Barker, that will be all.’

Harry left and headed for Bermondsey and to the address the governor had given him. He changed his mind when he saw the attention his Rolls was getting from bunches of sinister-looking men on street corners. ‘Turn around, Becket,’ he ordered. ‘We’ll leave the car somewhere safe and take a hansom.’