‘I’m not sure ghosts “hang” quite the way you imagine,’ said Nightingale, and with a quick glance to be sure that Molly wasn’t watching, he slipped his half-full plate under the table. Toby’s tail banged against my legs as he snaffled it down.

‘We need a bigger dog,’ I said. ‘Or smaller portions.’

‘See if he won’t talk to you tonight,’ said Nightingale. ‘But remember that our Nicholas wasn’t a reliable witness when he was alive – I doubt his veracity has improved since his demise.’

‘How did he die?’ I asked. ‘Do you know?’

‘Died of drink,’ Nightingale said. ‘Very enjoyable.’

*

Since Toby was our official ghost-hunting dog, and because he had begun to waddle alarmingly when he walked, I took him with me. It’s a half-hour stroll from Russell Square and the Folly to Covent Garden. Once you’re past Forbidden Planet and across Shaftesbury Avenue, the direct route takes you down Neal Street, where the cycle courier had died. But I figured if I started avoiding certain streets just because somebody’d died on them, I’d have to move to Aberystwyth.

It was late evening and not all that warm, but there was still a crowd of drinkers outside the gastropub. London had come late to the idea of outdoor café society, and it wasn’t going to allow a bit of a chill to get in the way now – especially since it had become illegal to smoke indoors.

Toby did pause close to the point where Dr Framline had attacked the courier, but only long enough to pee on a bollard.

Even at closing time Covent Garden was packed. The post-performance crowd were emerging from the Royal Opera House and looking for somewhere to have a bite to eat and a pose, while clusters of young people on school-sponsored holidays from all over Europe exercised their time-honoured right to block the pavement from one side to the other.

Once the cafés, restaurants and pubs in the covered market shut down, the piazza emptied quickly and soon there were few enough people about for me to risk a bit of ghost-chasing.