Paint splattered police officers look on during clashes outside Top Shop on Oxford Street, during marches in protest at government cuts on March 26, 2011 in London, England. Thousands are taking part in the Trades Union Congress (TUC) organised march to Hyde Park where a rally will take place. Police say they are deploying 4500 officers. (Photo by Dan Kitwood/Getty Images)

A couple dressed as caricatures of Prime Minister David Cameron and Lady Thatcher mime scissors with thier hands during a march in protest at government cuts on March 26, 2011 in London, England. (Photo by Peter Macdiarmid/Getty Images)

A protestor holds a smoke flare during clashes with police during a march in protest at government cuts on March 26, 2011 in London, England. (Photo by Peter Macdiarmid/Getty Images)

Protesters climb on a statue following a mass rally in Hyde Park in protest at government cuts on March 26, 2011 in London, England. (Photo by Oli Scarff/Getty Images)

Protestors attack a police vehicle as violence breaks out during a march in protest at government cuts on March 26, 2011 in London, England. (Photo by Peter Macdiarmid/Getty Images)

A man wearing a pig mask looks at police standing near Parliament as a march in protest at government cuts passes through Whitehall on March 26, 2011 in London, England. (Photo by Peter Macdiarmid/Getty Images)

Protesters take to the roof of Fortnum & Mason on Piccidilly on March 26, 2011 in London, England. (Photo by Dan Kitwood/Getty Images)

A woman dressed as a clown jokes with police during marches in protest at government cuts on March 26, 2011 in London, England. (Photo by Dan Kitwood/Getty Images)

In this photo illustration The Metropolitan Police Twitter feed is displayed on a smart phone as the march in protest at government cuts gets under way on March 26, 2011 in London, England. (Photo by illustration Peter Macdiarmid/Getty Images)

Paint-covered police officers chat outside a branch of Topshop following a mass rally in Hyde Park in protest at government cuts on March 26, 2011 in London, England. (Photo by Oli Scarff/Getty Images)

An anarchist demonstrator breaks the window of a Caffe Nero with a temporary bus stop during a march in protest at government cuts on March 26, 2011 in London, England. (Photo by Peter Macdiarmid/Getty Images)

Riot police stand in front of a burning barricade in Jermyn Street during clashes with protesters after a march in protest against government cuts on March 26, 2011 in London, England. (Photo by Peter Macdiarmid/Getty Images)

A mass march in protest at government cuts sets off from Embankment on March 26, 2011 in London, England. (Photo by Peter Macdiarmid/Getty Images)

Police officers and protesters clash on Piccadilly during marches in protest at government cuts on March 26, 2011 in London, England. (Photo by Dan Kitwood/Getty Images)