We are all there on the roof, crowded together to get into the picture frame. Spreading across the ground are the thin shadows of TV aerials. Surprised by the self-timer some of us are caught at unexpected angles as we jostle for a good position in the photograph but because the light is so bright everyone is in sharp focus and is clearly recognisable. Most of us are laughing or smiling as we squint into the glare. Freddie is drinking from a red can of beer. The colours are striking: there are the reds, blues and whites of T-shirts, shorts, dresses; a half-peeled orange; a halo-yellow cycling cap; the wide stripes of a deckchair. And over all of this is the deep blue of the empty sky — the colour of memory.