That day was the day that Duke of Edinburgh (the Queen's husband) would be out on the streets, so, the freedom-loving people of Great Britain started to come out and demonstrate! First, they set up camp along the roads he would surely pass.
The police officers were standing guard.
The demonstrators somehow ran out, too fast, didn't manage to take a picture. So they were pinned down.
The guy in the background still ignored everything as before.