After a filthy, arduous bus journey home, I'm looking forward all the more to swimming in the Øresund next week.

The bus was packed. I sat to the right on the top deck, on a forward-facing seat, with an empty, single, side-on seat right in front of me, behind the stairwell. At each stop, people appeared at the top of the stairs, looked around for an empty seat, then dipped back down again.

No-one saw the empty seat, so it remained empty for the duration of the journey. It struck me that no-one could see it because it just wasn't what they were looking for.