I’m thinking of these embarrassing notes when the first of two surprising things happens on the journey home from Covent Garden. The first of the surprising things starts when the doors open at Oxford Circus and four men get on the tube, already grinning as they leap on board, a quartet of fizzing energy. They have instruments strapped to their fronts – a violin, a trumpet, an accordion and a set of spoons – and a square black box, which they place on the floor between the two sets of doors. The man with the spoons turns a knob on the box and, with a whine and a twang, the recognizable opening bars of ‘La Bamba’ strike up and the four men launch into it with great exuberance, the man with the spoons slapping them on his thighs and enthusiastically providing the vocals. It sounds great. I’ve always hated that song; it was one of three songs guaranteed to clear me from a dancefloor when I was a teenager: the other two were Lulu’s ‘Shout’ and Phyllis Nelson’s ‘Move Closer’. Particularly that last one. Slow dances. Ugh. Dad used to come in with all the other dads to stand in the corner of the hall ten minutes before discos ended, despite all my pleading – the only father who couldn’t see that I was the only one not snogging a boy in the middle of the dancefloor.

A few of my tragic notes were written after getting home from these soul-scouring school discos. The pen with the different colours would come out and I would scribble my questions, my hopes and my dreams, and secrete them at the bottom of the sewing box, far from anyone’s eyes. Anyway, these men make ‘La Bamba’ sound bouncy and brilliant. Even the most hard-hearted tube-goers can’t help but smile. The carriage is literally rocking.

The surprising thing is that Dad’s foot starts tapping. There it is, Dad’s right foot, in black Adidas Italias, tapping in time to ‘La Bamba’, on the floor, next to his cane. I look from the foot to the men with the spoons and the trumpet and the violin, then back again, and I smile too. It’s some kind of miracle.

The second surprising thing is when I look at my phone just before we rumble into Chalk Farm station, there’s a text there from Salvi.

Lovely to meet you, Prue. I’ll call you tonight.