He’s grumpy; he’s been grumpy all morning – is he already regretting this as much as I am? The street outside The Palladian is busy and the people streaming past are already staring at the blind man and his coral-clad companion, and I worry if we step out we’ll be swallowed up by them, carried along, out of control, but ‘OK,’ I say, and I lock the door and put the keys in my cross-body bag.

My sundress is a bright coral maxi dress I bought from Loved Before three or four years ago. It’s been hanging in the wardrobe in Angela’s old bedroom ever since. I’ve taken it out often, just to look at it. It’s beautiful and it isn’t really me (it should ideally be worn by a twenty-something Instagram influencer with Pinterest hair), but I feel I want to make an effort somehow, for this. This thing I don’t really want to do. I’m not equipped to guide my father. I can’t even guide myself through my own life to any satisfaction. I don’t know what we’re even doing here, with the sun beating down on us and a long road ahead. But this morning I really felt a need to take this beautiful maxi dress off its pretty padded hanger and put it on.

‘Ready for the off, then?’ says Dad gruffly.

It would be so easy to turn Dad around, step back into the cool, dusty lobby and head back up the stairs to The Palladian for a glass of cold lemon squash and a KitKat.

‘Yes, ready,’ I say.

Dad, who is standing to my left, places his hand on my left arm, just above the elbow and I straighten my arm. This is how we do it when I take him anywhere – the default positioning we slip into automatically. We start to walk slowly along the flank of the tube station, the closed windows of The Palladian above us and the dark red tiles of Chalk Farm tube station gleaming under bright sunlight.

‘Do you want to pop into the Stop n’ Shop for anything?’ I ask him. I’m stalling, I know. My dress feels too swishy and rather ridiculous.

‘No,’ Dad says. ‘But let me feel the tiles.’

We step closer and Dad places a flat palm on one of the oxblood tiles. I put my hand on another and it is hot to the touch. Dad looks like he is drawing energy from his tile. He loves this tube station – everything about it. The tiles, the arches, the ticket hall, the cornicing and the Arts and Crafts dado rail friezes, featuring the acanthus leaf. All the details people don’t notice and he can’t any more.

‘Chalk Farm has the longest frontage,’ he says, ‘of all the underground stations in London – and the most tiles.’