‘You can see the hole from up on the footbridge.’

Keeping as far from the tracks as we could, we made our way under the footbridge and headed for the concrete mouth of the tunnel under the school. Graffiti covered the walls up to head height. Carefully sprayed balloon letters in faded primary colours overlaid by cruder taggers using anything from spray paints to felt tip pens. Despite a couple of swastikas, I didn’t think that Admiral Dönitz would have been impressed.

It kept the drizzle off our heads, though. There was a piss smell but too acrid to be human – foxes I thought. The flat ceiling, concrete walls and the sheer width that it covered meant it felt more like an abandoned warehouse than a tunnel.

‘Where was it?’ I asked.

‘In the middle where it’s dark,’ said Abigail.

Of course, I thought.

Lesley asked Abigail what she thought she was doing coming down here in the first place.

‘I wanted to see the Hogwarts Express,’ she said.

Not the real one, Abigail was quick to point out. Because it’s a fictional train innit? So obviously it’s not going to be the real Hogwarts Express. But her friend Kara who lived in a flat that overlooked the tracks said that every once in a while she saw a steam locomotive – because that’s what you’re supposed to call them – which she thought was the train they used for the Hogwarts Express.

‘You know?’ she said. ‘In the movies.’

‘And you couldn’t watch this from the bridge?’ asked Lesley.

‘Goes past too fast,’ she said. ‘I need to count the wheels because in the movies it’s a GWR 4900 Class 5972 which is 4–6–0 configuration.’