Before it all kicks off, Colette leans from the terrace and points downriver. ‘That brown building is a pub called Samuel Pips’

‘Pips are what you get in oranges. It’s pronounced Peeps.’

‘Oh, always the English teacher!'

The view from the Tate is muddied, like a beginner's attempt at watercolour. The Thames has a tint of greegage under a plum-bruise sky; the grey dome of St Paul's squats like a cantaloupe on the other bank.

Colette places a slice of apricot tart on the table and indicates two forks. But there's an apple in my bag. Besides, I’d eaten a muffin at the National Film Theatre, where tickets for the pensioners' screening of Truffaut were sold out.

So, a stroll to the Tate instead. My name still on the computer, I'd revive my membership and we'd plan our visit, pencilling ticks on the programme.

But we'd forgotten it’s half-term. The Turbine Hall is filled with the very age-group we’d been glad to see the back of. Most are just milling about, shouting; some are running up the down escalators.

‘I had the same nightmare at the start of every term’, I say.

‘I didn’t sleep’

Suddenly, there's a loud beeping and a grabbing of coats and bags. Then six winding flights of hemmed-in panic.'Do you smell smoke?'. A young woman struggles with a red buggy while Colette and I recall students setting off school alarms for fun during the IRA scares.

Outside in the welcome chill, it’s as if a pop concert is about to begin, under the cherry blossom.

We laugh. 'School’s out. Come on, let's go visit Samuel Pips', I say. I'm wondering if he had his own suspicions, unmentioned in his diary in 1666.

But they didn't have half-term in his day, did they?