Today's demo in the centre of town was about Guantanamo Bay. I didn't have time to stay and watch, but it seemed to be a low-key Scottish affair. Consultation with a bobby (policeman) is going on at the left, and apparently being recorded by the girl with the sound boom. Over to the right there's a bit of friendly local banter from the passer-by in the foreground.
I've since discovered that the event was organised by Amnesty International, and took the form of a march along Princes Street to the US Embassy, where a sack of letters to President-Elect Obama was presented and a message to him read out.