‘An unfortunate consequence of Dr Simpson’s famous discovery,’ McLevy said. ‘A gang of masked men robbed a carriage on its way north from Berwick. They surprised the guards and attempted to subdue them by the highly unusual – and as it turns out highly ineffective – method of holding cloths to their faces. The cloths were discarded at the scene and when recovered still retained the characteristic smell of chloroform.’

Now there could be no question McLevy was talking about Flint’s men. This had been what he wanted the chloroform for. The arrogant fool must have assumed Raven’s warnings were mere bluster. Now he knew otherwise, and to what cost.

‘The cloths failing to have the effect this crew presumably imagined, there ensued a struggle, during which one of the coach guards discharged his weapon.’

‘And what of the guards themselves?’ Raven asked, concerned as to how grave this crime might be to which he was now connected. ‘Were they injured too?’

‘They were beaten and bound, but they will recover. My concern is with what was taken. If I discover who was shot, it ought to be enough to lead me to the goods.’

This was why Flint had brought Raven in. They could not take the Weasel to another doctor, for fear word of the injury might spread and thus betray them.

‘What did they take?’ Raven asked.

‘A strongbox being transported to the Exchange. It contained certificates of stock holdings.’

‘What use are such documents?’ asked Simpson. ‘They bear the owner’s name, do they not?’

‘They bore no name as yet: that is why they were targeted. They were being transported from a printing works in Newcastle ahead of a stock offering. With the aid of a talented enough – and corrupt enough – calligrapher, they could be rendered indistinguishable from legitimate documents.’

‘I do hope my Mr Quinton isn’t eavesdropping,’ Simpson said, ‘or I will have to offer him a raise in order to keep him from temptation.’

Raven laughed, though he was barely listening. He had only asked the question in order to appear natural and to conceal the turmoil going on inside his head.

If he told McLevy what he knew, it would surely rid him of Flint for ever. But no sooner had this possibility opened before him than he saw that it was not so simple. Flint was too clever to keep the stolen goods anywhere that could be tied to him. That was probably where he had gone last night when Gargantua responded so anxiously to Raven’s question as to Flint’s whereabouts.

Furthermore, they would surely have disposed of the Weasel’s remains by now. There would be no evidence, but were the police to come enquiring, Flint would know who had pointed them there. And there would be repercussions. Reprisals. Much worse than anything he had experienced before.