A hard core of around 1,000 protesters played cat-and-mouse with police around the West End, among them known and identified troublemakers. Around 6,000 people gathered in Trafalgar Square - including 4,000 from a TUC march - where there were reports of stones and cans being thrown at police as anarchists attempted to hijack the event. Earlier in Oxford Street, traffic halted and tensions rose as around 1,000 protesters mingled with lunchtime shoppers and kicked 20 inflatable footballs around, some as big as 3ft across.