He hadn’t given the painting any real notice before, but now he turned to give it a better look. He was no art connoisseur but it seemed to him the typical eighteenth-century portrait, a highly posed hero shot of a nobleman wearing one of the powdered wigs that had been all the rage back then, and shiny body armour draped across one shoulder with a splendid red cape. The intended effect had no doubt been to depict the subject as gallant and virile, a righteous and chivalrous warrior, but to Ben’s eye it came across as somewhat camp and affected.

But there was something else about the picture that made Ben look twice. As he studied the face of the man in the portrait he realised that, although a good few years younger, it was the face of the real-life Charles Stuart standing with him in the room. This maniac had had an artist knock up a reproduction of an old painting in his own likeness.

Stuart gazed at the portrait with the look of a man who had seen God. He slowly nodded. ‘Indeed, it’s my honour to belong to his royal bloodline.’

‘That’s quite an impressive pedigree, isn’t it?’ Ben said. ‘To be able to trace your heritage straight back to a real Scottish hero.’

Stuart gave a haughty smirk and was about to reply when Ben went on, ‘A real Scottish hero who in fact was an Italian coward, who dressed up as a woman to escape the enemy while his loyal followers who stood their ground on the battlefield were slaughtered and persecuted. So much for genetic superiority. I wouldn’t be too proud to belong to that line.’

Stuart’s smirk died away and became a hard glare.

‘Still, with all that gold up for grabs,’ Ben said, ‘I’d have been surprised if other real Scottish patriots like yourself didn’t try to stake their ancestral claim. I hope you’ve got ironclad proof of yours.’

‘Don’t you worry about what I can prove or not. The gold’s mine, and I’ll have it.’

‘Only on my terms,’ Ben said. ‘You’ll get it once I get what you have to trade me in return.’

‘I have a reputation as something of a tough deal-maker,’ Stuart said, getting angry now. ‘Don’t push your luck, because I don’t tolerate it when people try to stand in my way.’

‘Looks to me like I’m in your way,’ Ben replied. ‘Whether you tolerate it or not.’

Stuart stabbed a furious finger at Ben. ‘Here’s how it’s going to be. I don’t do deals with people like you, so stick your terms up your arse. But make no mistake, you will talk to me.’

‘You’d have to say “Please”,’ Ben said. ‘Or try very hard to make me.’