About 25 tents were pitched next to Nelson's Column at 1.30pm after a group of 200 protesters broke free from the main march, which was protesting about the rise in university tuition fees and education cuts.The breakaway group pledged to stay in the square indefinitely, mirroring the occupation at St Paul's Cathedral.
About an hour later police removed the protesters, saying they had breached section 12 of the Public Order Act by deviating from the official protest route.
The success of the policing operation was in part attributed to the fact that Scotland Yard had 4,000 officers on patrol, the largest single body of officers policing any event since the summer riots.
The attempted occupation was the only notable incident of an otherwise peaceful protest. Last night only 24 arrests had been made despite an estimated 10,000 protesters turning out.