Anarchists went on the rampage in central London as hundreds of thousands of people marched in protest at government cuts.

Police fought mobs of masked thugs who pelted officers with ammonia and fireworks loaded with coins.

The anti-capitalists started fires and smashed their way into banks, hotels and shops, bringing chaos to Britain's busiest shopping street.

The violence began as Ed Miliband, the Labour leader, addressed a TUC rally of at least 250,000 peaceful protesters in Hyde Park who had marched from Westminster to demonstrate against government spending cuts.

As he spoke, an apparently co-ordinated attack began on shops and police in Oxford Street as a mob tried to storm into shops including Topshop, BHS and John Lewis.

MPs and retailers said the scenes damaged Britain's reputation around the world.

The move was the first of a string of actions by anarchists in which:
  • There was violence last night in Trafalgar Square, with protesters setting banners ablaze and throwing missiles including broken bottles at police officers. As police contained protesters around Nelson's Column, there were running battles in Strand. Close to Charing Cross railway station, a fire was started near shops;
  • Fortnum and Mason, the department store, was occupied by 200 "anti-cuts" protesters who smashed windows and knocked over displays;
  • A huge fire was started in the centre of Jermyn Street, the Ritz hotel was attacked with dustbins and a "Trojan horse" set on fire in Oxford Circus;
  • Banks were broken into, their windows smashed and daubed with graffiti reading "smash the bank";
  • Windows were smashed in New Bond Street and running scuffles took place on Piccadilly, where a Porsche car showroom was attacked.
Anarchist groups had spent weeks preparing the action on Facebook and Twitter and even posted a map directing people to the time and location of where to attack shops.

More than 4,500 police officers were on duty for the march but seemed powerless to stop the violence, which began when a group of activists bent on trouble peeled off into the busy shopping area.

After five hours of running battles, there were 202 arrests. At least 30 people, including five police officers, were injured. Police said the anti-capitalists threw lightbulbs filled with ammonia at them.

Senior officers watched the chaos from a command room in Scotland Yard where they had invited civil liberties activists to monitor a "softly-softly" approach after criticism of their tactics at earlier student protests. At one point, they used Twitter to warn the occupiers of Fortnum and Mason they would be arrested.

They ordered limited use of "kettling" to contain the rioters but admitted that such was the scale of the violence, they could not protect property.

Mr Miliband said: "I unequivocally condemn those who have committed acts of violence. There is no excuse for it. It is unlawful and wrong." Retailers, who were assured by ministers before the march that their premises would be safe, were privately furious at the damage.

Chris Heaton-Harris, a Tory MP, said Britain's reputation had been damaged by the "mindless thugs". Brendan Barber, the TUC general-secretary, said he "bitterly regretted" the violence but insisted that the march was important.