We arrive at the iron bridge, turn right at the towpath and go down to the locks. There are sloping flagstones to negotiate; areas of welcome shade. Volunteers are sweeping the lockside brickwork free of dust and weeds; a man is turning the lock of a narrow boat with a giant windlass. I describe everything to Dad as best I can: the canal boats waiting to pass through the lock; the green algae on the undisturbed sections of water; the weeping willow that arcs over the canal and nods in the sun. It’s tranquil here, compared to the street. I came here quite a lot with my friend, Kemp, the photographer. He lived not far from here, in a houseboat at Wenlock Basin. I wonder if he’s still there. He liked to take shots of the water and the weeping willow and the boats, and I would watch him and try not to blurt out that I loved him.

Dad nods as I speak, his face set and unreadable. After a while we return to the bridge and continue down Camden High Street in the direction of Camden Town tube station, with the milling souvenir seekers dazzled by sunglasses and T-shirts and jewellery and Union Jack paraphernalia crammed below shop awnings under coloured buildings. Dad asks me if the record shop is still here.

‘Which record shop?’

‘Pete’s Records? The other side of the road.’

I look. ‘Yes, it’s there.’

‘Come on, then.’

We avoid a pair of chuggers in orange vests and cross the road to the record shop. Dad used to live for music. It used to be in the centre of our Venn diagram, if one existed for Dad and me: a common love, with architecture in the sole portion of Dad’s circle, and absolutely nothing in mine. Dad has been a bit of a Mod since the late 70s, when he got swept up in the revival; he loves all that music and its tributaries. When he went blind in the summer of 1980, it was not long after the film Quadrophenia came out (he’d been to the cinema to see it three times with Jack Templeton), and when it was out on video he’d listen to it over and over again, reciting the dialogue. He had The Who soundtrack, too. Quadrophenia used to drive Angela and me mad.