‘I try to lighten the mood,’ he said. ‘This is not the most pleasant job, but it pays the bills on my houses in Edinburgh and Kelso.’

‘Do the people in Kelso know what you do?’ I asked, for no one had mentioned it, and the River Inn had been a gossiping place.

‘Oh no, they would treat me differently if they knew,’ he said. ‘A hangman wears a hood for a reason. And the folks of Kelso are of a low intelligence and would not understand that hanging is a craft.’

He was truly the most despicable of men. As he took up his measuring stick and proceeded to ask me to stand straight, I imagined he was well capable of poisoning his wife. Poor Kitty.

And that was when it came to me.

‘Dr McTavish,’ I said, keeping my voice low so that he had to lean in towards me to catch my words, ‘have you seen our mutual friend, the dear Mrs Rose, since she absconded?’

‘Alas, no,’ he replied in a whisper, his lips almost flickering at my neck. ‘But if I did see her, I do not know what I would do first: kiss her or hang her for the way she treated me, by running off like that.’

‘Mrs Rose did talk quite boldly of you,’ I said.

He hesitated, just for a moment, before carrying on in his morbid task.

‘Step on the weighing platform,’ he instructed.

I did. Now I was taller than him and I stood in front of him, facing the wall whilst he adjusted the weights.

‘Mrs Rose told me a funny story – not funny like your quip, Doctor, but a strange tale that made my hair stand up on end, so gory it was. A tale about you.’

This time he did stop.

‘And what was this tale?’ he hissed.

‘Well, I hardly dare tell it, sir, for it paints you in a terrible light, but if you insist,’ I answered.

And he stood and listened to what Mrs Rose had said about him: that she thought he had poisoned poor Kitty, for she dropped dead out of nowhere, and Dr McTavish was a master of all sorts of potions. And that Dr McTavish was sorely fed up with his wife and would do anything to get her out of the way.

‘A chaste marriage, that’s what you had, and that’s why you employed the services of Mrs Rose. Your wife would not give you your conjugals and was, by all accounts, a harridan to you, to boot.’

And although I could not see his face, for he was behind me, remember, I could tell by the rapid way he breathed that he was suddenly feeling very grave indeed.