Violent clashes kicked off in London's financial district late on Wednesday after protesters demonstrating against the G20 summit were penned in by riot police for several hours.
Demonstrators who had been held outside the Bank of England for much of the afternoon at the junction of several closed-off streets began charging police lines, hurling glass bottles and sticks.
Protesters torched an effigy of a banker hung from a lamp post, and bits of the burning figure were thrown at police.
Some demonstrators began tearing down the crush barriers holding them in and dragged them towards the police, before riot police surrounded them.
There had been violence earlier following a march by thousands of anti-capitalist protesters but this had calmed down by late afternoon.