‘Who is this person?’ Gerald asks, fork halfway to his mouth. ‘Ought I to know of her?’

‘One of the Forty Thieves, Daddy. I wrote about her for the Gazette.’

‘Ah. Yes. Of course.’ He has not read the article.

‘I don’t need Harriet to tell me about Ruby Mills,’ Arthur says, more to his wife than to the company at large. ‘I encountered her myself in one of the vilest drinking dens in Southwark. She and her associate robbed Enderby’s jeweller two weeks ago. They nearly killed Mr Enderby, and his daughter is a nervous wreck.’

‘And then you arrested her?’ Isabel asks, anxious about the turn in the conversation. ‘This Ruby Mills?’

MacKenzie’s face is ugly in the candlelight; his neck bulges above the starched white collar he is wearing. ‘No. I know she did it, but unless we catch her with the stolen goods about her person or her property, then it’s difficult to bring a trial.’

‘Wouldn’t Enderby testify against her?’ Gerald asks. ‘Surely that would be enough? He had a good look at her, yes?’

‘No, it’s not enough. Mr Enderby is an old man with a heart problem. Lost all his boys in the war. The strain of appearing in court would be too much for him. Besides, if we can’t find the jewels, then Ruby Mills and her accomplice will hire the sort of lawyers who can turn an honest man’s eyewitness account into a rambling stream of nothing.’ He shakes his head. ‘I’ve seen juries acquit villains often enough because the defence barrister twists the words of the witness.’

‘I wonder why they do it? Why they steal?’ Mary asks of no one in particular. ‘The women, I mean. Do they become involved with criminal men? Allow themselves to be corrupted?’

‘They’re born into it,’ her husband says firmly. ‘If you saw what I saw, daily, you’d understand. The squalor, the iniquity, the lawlessness over the river. Ruby Mills will have been picking pockets when she ought to have been in school. The older ones teach the younger ones, and so it goes on. The lives they lead are hard and grubby. They might dress like ladies, but they are anything but. Foul, vicious creatures, all of them, and not, I should say’ – he gives Harriet a severe look – ‘the sort of women to be glamourised or praised in any way.’

‘That’s what I said,’ Isabel puts in. ‘When Harriet said she wished to write about them. Don’t give them any attention, I told her.’

‘I find them fascinating,’ Harriet says with a shrug. ‘Their ingenuity, even more than their style. Foul and vicious they may be, but these women seem so able to run rings around the police.’ She takes a sip of her wine and gazes innocently at Inspector MacKenzie. ‘Just think what they might be, were that intelligence harnessed for good.’