Plastic cordons across Whitehall, police cars parked where my bus should come. So I carry on walking, under Admiralty Arch. A tunnel walled by plane trees, swooping towards the baleful glow of the Victoria Memorial. No bikes in the dock, it’s like everyone’s fled before the aliens flatten the city, the Mall is leaking green and red, pulled out of the traffic lights, slicked by rain, the only animate features on the long trudge towards Buckingham Palace.

  I’m tangled up in cordons and tripod signs, clambering over them to find the pavement; a police car flashing its lights. Slowly the traffic gathers again, a bus caroms past, taxis roll, racing past glass foyers and revolving hotel doors where the concierges stand in frogged greatcoats, conjuring a London from long-ago. Past Victoria station and the long white coaches, like stretched-out ambulances waiting to be filled. I click for a bike and pedal across the puddles; and it’s only now that cars are passing me, and London’s breathing again.

  A sniff of a joint on Chelsea Bridge, a couple laughing, a queue at a burger stall, slow reminders that London doesn’t get shushed all that easily. I’m watching the drops of rain splattering my trousers, my seat’s too high so I’m squirming across it, hoping I’ll find a slot when I reach the docking station. Little details, tonight they feel heightened; because these are the practicalities, these are the things you can do something about.