It’s not going too well. The tube journey here was a nightmare; the crowds have been a nightmare. We have been jostled and bumped into; three people have tripped over Dad’s cane; one has trodden on my foot; and a small child scooted between us on a pair of Heelys (which I’m not sure are even a thing any more) as we walked, Dad holding on to my arm, as though we were some kind of human arch at a skate park. We’ve walked up and down and looked at the boats. We’ve had a lunch of falafels with tahini sauce from a market stall. We’ve trudged backwards and forwards along a row of identical white-stucco four-storey mansions while I’ve made a fist of describing them to Dad and he’s corrected me on my naming of several architectural features. Actually, that bit was all right. We were in the shade and there were fewer people gawping at us like constipated guppies.

We’re now walking, with our ice creams, away from the hipster ice-cream seller in his shiny metallic food cart and towards an area of shade on the walkway adjacent to the canal. My scoops are wobbling precariously on their gluten-free cone. I remember, when I was a little girl, I was always dropping ice creams, often in the middle of the street, and Dad would never get cross with me but always buy me another one, and when I finished eating he would pull a big blue hanky from his trouser pocket and wipe my face laughingly with it.

‘Let’s sit here,’ I say, guiding Dad to a picnic table that is half in mottled sunlight and half in the shade. I take the shade and both ice creams, depositing them in a nearby bin.

Dad sits down and exhales, stretching his legs in front of him. The waterway is busy this afternoon. Multicoloured houseboats are lined up along the edges of the canal. Dozens of them – I try not to think about houseboats, or friends with green scarves, or Polaroid pictures. Instead, I concentrate on a pleasure cruiser gliding down the centre, people in hats and sunglasses gazing out of its windows. Barges creep along the water, owners at their stern or bow looking as happy as people ever might. An approaching vessel startles by, sounding its horn. A woman sitting astride a barge that is coming the opposite way and heading languidly into its path shouts for a ‘Cliff’ and a Cliff appears from below deck with a rope in one hand and a beer in the other, and springs into action with what I believe to be a rudder and a do-or-die spirit. The two barges are saved from near collision with nary a cry of ‘Easy mate!’ and a couple of sharp intakes of breath between their owners.

‘Argy bargy?’ asks Dad.