‘He did and he has,’ said Sellers. ‘They want a bit more time to put their formal report together, but when I pushed, what I got was an official 80 per cent and an informal “Yep, that letter’s from Billy”. I just got off the phone with Coulthard – there’s no doubt in his mind.’

Simon made an impatient noise. ‘There might be no doubt in his mind that the letter to Sondra Halliday and the lines from poems in the little white books were written by the same person, but we need to remember we don’t know for certain that person’s Billy. It’s just about possible that someone’s giving out white books, and someone else is doing the killing. I know we’re assuming they’re one and the same, but we shouldn’t forget that’s all it is: an assumption. We especially shouldn’t forget it now that this comedian’s turned up alive and well, saying she was given a book early last year. That’s a big blow to our presumed pattern, isn’t it?’

‘I think James Wing’s right,’ said Gibbs. ‘We need to alibi out Sondra Halliday. She’s ended up centre stage. First she’s writing about Billy, now he’s writing to her … We need to focus on her.’

‘Want me to talk to her again?’ Sellers offered.

‘I didn’t want you to talk to her yesterday,’ Simon reminded him. ‘I wanted Charlie to do it. I wonder …’

‘Lonely as a cloud, but not as pretty,’ Proust contributed.

‘If Billy was the man who gave Kim Tribbeck the white book, he wasn’t to know she can’t match a memory of a place to that place’s name because of the number of shows she does in one tour. Did he want her to say to us, “He was at my gig in, say, Falmouth” because he lives nowhere near there? That could explain why on that one occasion he let himself be seen, if he wanted to mislead us.’

Sam frowned. ‘It’d be a risk for him. He’s surely safer if no one’s seen his face.’

‘Kim got her book first, and could well have been Billy’s first intended victim,’ said Simon. ‘We should remember that. It might mean he hadn’t settled on an optimal M.O. yet. I’m sure Kerensa Moore’d tell us that sometimes, with serials, the first kill’s different – more spontaneous, less thought through – before the scrote sorts out his ideal routine.’

‘I don’t need Moore to tell me that,’ said Gibbs. ‘We all know it’s true.’

A waitress appeared at their table with a plate of steaming hot food in each hand. Everyone was having the house shepherd’s pie with extra Tabasco sauce. Gibbs pointed to the table in front of him to ensure he was served first.