Part of Scotland Yard's public website was disrupted as thousands of masked protesters descended on central London for the Million Mask March organised by hacking group Anonymous.

Wearing characteristic Guy Fawkes masks, supporters of the mysterious online collective crowded into Trafalgar Square on Saturday evening with scores of police on hand to keep order.

At about the same time, the news section of the Metroploitan Police website crashed.

Confirming that Scotland Yard was now investigating what caused the website problems, a Met Police spokesman said: “The Met News web address news.met.police.uk which is run on a separate platform to the normal Met police website is now working fine.

"During the time the Met News web address was not working – between the evening of Saturday, 5 November and the morning of Sunday, 6 November – an alternative Met News web address was used and worked with no issues.

"We have contacted our supplier regarding the temporary disruption to the usual Met News web address.

"There are no security issues with the Metropolitan Police Service website."

Thousands join Million Mask March in central London

Saturday's protest began peacefully, with several participants climbing the base of Nelson's column and chanting the slogan "one solution, revolution".

There were, however, chaotic scenes as riot police moved in to make an arrest in Trafalgar Square near 9pm, the time conditions imposed upon the demonstration said it should end.

A group of protesters surrounded and charged at the officers, shouting "f*** the police" and "police brutality". Several glass bottles were thrown as police escorted another protester away.

By the end of the evening, police had made 53 arrests for offences including obstruction, possession of an offensive weapon, public order and drugs. A small number of fireworks were thrown, but they did not cause injury.

The Metropolitan Police said "the majority of those taking part were peaceful" but there were "pockets" of disorder.

Scotland Yard had imposed restrictions on this year's event amid concerns over disorder, limiting the march to a three-hour period between 6pm and 9pm on a prescribed route between Trafalgar Square and Whitehall.

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The restrictions were imposed after four officers and six police horses were injured after missiles and fireworks were thrown at them during last year's march.

Days before this year’s march, Commander BJ Harrington, of the Met's Public Order Command, issued a public statement in which he recalled last year’s disorder and said: “We know the public would much rather have police officers on the streets in your neighbourhood rather than dealing with masked criminals seeking to run amok in central London.

“This is not peaceful protest. Any claim that somehow the police are ‘responsible’ for this violence is simply not borne out by the facts.”

With nearly 20,000 people using Facebook to say they intended to attend this years’ march, Mr Harrington warned: “My message is simple: if you want to protest peacefully, that is your right and we want to work with you. If you commit criminal acts – that is not peaceful protest – and you are liable to be arrested."