‘Yes, a couple of places, since I last saw you, Vince,’ answers Kemp and I think of Dad showing him my paintings and feel slightly sick. ‘A disused police station and an old orphanage, in Buckinghamshire, that’s been closed since the eighties.’

‘Sounds fascinating,’ says Dad.

‘They really were, and I’ve got loads more coming up. On Tuesday I’m off to another derelict psychiatric hospital and next Saturday I’m going to the Hornsey Wood Reservoir, underneath Finsbury Park.’

‘Hornsey Wood?’

‘Yeah.’

‘I know that place,’ says Dad. ‘I went down there once when I was qualifying. It’s a fine example of Victorian architecture. I like to read up on it sometimes. Can I come with you?’

‘What?’ I say, in the middle of them both, as we take another couple of steps in the queue. Dad and Kemp have been batting across me like jovial players in a tennis match. ‘What are you talking about, Dad? What even is it? Like, a sewage works? You can’t go there!’

‘It’s a reservoir,’ says Dad, ‘and people go down there all the time. People like Kemp – urban warriors or whatever they’re called.’ Kemp grins, and I find myself shaking my head disapprovingly at him, but when he winks back at me, I abruptly stop. ‘Plus, they filmed scenes from the Sherlock Holmes and Paddington movies there. It’s perfectly safe. I’d like to go. Can I join you, Kemp?’

‘You can’t go to a bloody underground reservoir, Dad!’ I cry. ‘You’re blind, and it sounds really dangerous!’

‘“Avoiding danger is no safer in the long run than exposure,”’ says Dad, tapping his cane on the ground. ‘Helen Keller said that. And she was blind as well, you know.’

‘What’s your point?’ I ask.

‘My point is we can’t stay in all the time, avoiding things. I’ve realized that recently.’ He beams in my direction. ‘I’d like to go down there. You don’t have to parachute in or anything, Prue. There’s a hatch and a ladder.’

‘I don’t know,’ says Kemp, finally able to get a word in. ‘Prue might be right. It might be wise not to do that one, Vince. Sorry, mate. Perhaps you can come somewhere else with me.’

‘Oh, sciocchezze!’ replies Dad. ‘Tush! I could wait up top for you. You could go down and then come back up and describe it all to me. Maybe you’d even let me sit and dangle my feet down the hatch, so I can soak up the atmosphere. Have pity on the poor old blind boy and let him soak up a bit of the atmosphere,’ he pleads dramatically, in the voice of a randomly Italian Dickensian waif.