He found Ross looking at a lurid sign, a woman pictured lying in the gutter, blood dripping from her mouth, and a silhouetted caped figure running away. The sign was propped against a brick wall that looked as if it had been scrubbed clean of centuries of dock slime for the tourists. Or perhaps it was new, built in the old style.

She turned to look at him as if he was something on the Ops Board. ‘Why’d you text me the other night?’

‘And hello to you.’

She frowned at him, but at that point the tour guide arrived and took their money, and others who wanted to go on the tour started to arrive; he was relieved not to have to answer the question.

The tour was called, in dripping red letters, ‘Jack the Ripper Extreme’. Their guide was a Mr Neville Fennix – probably his stage name. He was dressed in a top hat, opera cape and evening suit, and he carried a silver-tipped cane. There were a large party of Italians and their translator, and another group who were talking in what Costain thought might be Korean. There were also quite a few younger people, students, several of whom were wearing what had now become known as the Ripper mask on the back of their heads to shade their necks from the sun. That bloody thing was everywhere now. Previously only a fraction of protestors had worn it; now it was their uniform. He’d seen T-shirts and online banners with the Ripper mask portrayed in those Obama ‘Change’ campaign colours or like Che Guevara, with slogans underneath such as ‘Occupy Hell’. The Ripper had put a face to the summer of blood. He had killed not just an MP, but now one of the most senior police officers in London, right at the point when the Met was creaking under the pressure of lack of resources and government meddling. If they can get to him, they can get to any of us, that’s what a spokesman for the Police Federation had been quoted in the Herald as saying, and the job cuts and the service cuts and every cut make every single one of us more vulnerable. The driver, Tunstall, had been released at the end of his ninety-six hours in custody, the main investigation having convinced a judge that they needed the maximum period of detention. Tunstall hadn’t changed his impossible story, though, and so now the media were also full of the news that he was ‘back on the streets’.

As Fennix took cash from the other tourists, Costain found himself glancing at Ross again. She was still looking interrogatively at him. He wasn’t going to be able to get away from her question.