One less thing to worry about, I thought. Perhaps I was going to get to see the match that afternoon after all.

I don’t know why I bother, I really don’t, because at that exact instant my phone rang and a voice identified herself as a British Transport Police inspector and asked did I know a certain Abigail Kumara and could I be a dear and come down to the BTP Headquarters in Camden and please take her away.

As it happened, I’d already been planning for just this sort of eventuality. But I’d counted on having more time to butter up Nightingale first.

I said I would certainly be round to get her just as soon as I cleared some things with my boss. The Inspector thanked me and wished me a Happy New Year.

29. Mornington Crescent

29

Mornington Crescent

I found Abigail in an interview room eating Burger King and reading a month-old copy of Jackie. The BTP had discovered her in the tunnel under my old school committing an act of vandalism. By rights she should have been returned home in disgrace with possible charges pending, but she’d dropped my name and the BTP had been seized by the spirit of goodwill or, more likely, a desire to avoid the paperwork involved.

I sat down opposite her and we stared at each other – she broke first.

‘I was finishing off the graffiti,’ she said. ‘You know the one the ghost was writing. In the tunnel where the Hogwarts Express goes. Before he’s, you know, squished—’

‘Why?’

‘I reckoned that if he got his message out he might get closure and move on,’ she said.

I didn’t ask where she thought the ghost would move on to.

‘I thought it would be a nice Christmassy thing to do,’ she said.

‘It’s the day after Boxing Day,’ I said.

‘We had to spend Christmas with Uncle Bob in Waltham Forest,’ she said. ‘I got a new coat – like it?’

It was blue, quilted and several sizes too big.

‘I’ve got you a Christmas present, too,’ I said.

‘Really?’ she said, and then gave me a suspicious look. ‘What kind of present?’

I handed it over and watched while she meticulously unpeeled the Sellotape before removing and neatly folding the paper. I’d given her a Moleskine reporter-style notebook that looks almost exactly the kind of black notebook that everyone thinks the police use, only we don’t. And even if we did, we’d be much too cheap to buy Moleskines – we’d get them from Niceday instead.

‘What am I supposed to do with this?’ she asked.

‘You’re going to make notes in it,’ I said. ‘Anything you notice that you think is unusual or interesting—’

‘Like the ghost?’