‘But why have you put yourself in danger, Harry? Haven’t you done enough? Can’t you leave it to others and come home to lead a normal life?’

‘I will, but only when this is finished. I have a personal score to settle with Monks. He shot and killed Annie’s father and her mother died of a broken heart.’

‘I was told it was a duel, fought over a gambling debt.’

‘George Blythe was my uncle and he was good to me when I was a boy, but he had a weakness for gambling and he became involved with Monks. He lost heavily and when Monks put pressure on him to pay back his debt of honour, it ended in a duel. Monks supplied the pistols and I’ve always suspected that the one George used had been tampered with, but it was a long time ago and impossible to prove.’

‘Are you certain? I mean it could have been that Monks was a better shot.’

‘Never. George was an army officer, trained in the use of firearms. One of the reasons why I started up the gaming clubs, apart from the obvious need to make money, was to keep Monks within my sights. If I couldn’t catch him any other way I had to make him think that I was a criminal, too.’

‘And the police knew about this?’

‘Not at first. I had to be very careful with my cover, but eventually I had to tell them what I was doing or face arrest. When I was sent to prison it was all arranged, as you know. Monks is no fool and he was getting suspicious.’

‘What are you going to do now? What is this trap you’re talking about?’

He shook his head. ‘I can’t tell you, Kate. I want you to return to Finsbury Square and stay there until I tell you it’s safe to leave.’

‘But we’ll be prisoners in our own home.’

‘If you can’t persuade your mother to be careful then you should take her back to Warren House.’

‘For how long, Harry? This could go on for ever.’

‘No. I told you, Kate. I am working to bring a case against Monks that is watertight.’

‘You say he’s a jewel thief and he steals works of art.’

‘Yes, what of it?’

‘Well, the simplest way I can think of is to put temptation in his way that he simply can’t resist. If I wanted to trap a jewel thief I would bait a trap with a priceless item of jewellery or an art collection and wait. Sooner or later he would be bound to take the bait.’

‘There’s only one flaw in that theory, Kate. Precious jewels are hard to come by, as are great works of art. Monks isn’t a fool. He’d see through something like that in an instant.’