Supporters of a far-right Hungarian political party were blocked from leaving a Tube station today as anti-fascists protested against their planned rally.
Dozens of protesters gathered outside Holborn station in central London to oppose supporters of the Jobbik Party, which is accused of holding strong anti-semitic views and fuelling hatred against Jewish and Roma communities.
Police officers lined up at the entrances to the station and erected barriers to prevent clashes between the groups, as anti-fascist campaigners waving placards chanted "Nazi scum, off our streets".
Jobbik leader Gabor Vona, who is said to have links with the far-right British National Party (BNP), had planned to speak to expatriates at a venue in Camden, a day before Holocaust Memorial Day.
But after more than a hour stood inside the station behind the police officers, the Jobbik supporters retreated and appeared to return to the Tube platform.
Scotland Yard later confirmed that the event in Camden had been cancelled.
London Assembly member and former Labour MP Andrew Dismore had written to Home Secretary Theresa May demanding that Mr Vona, founder of the now-outlawed Magyar Garda Mozgalom paramilitary guard, be banned from holding the event.
Mr Dismore, who as a Labour MP founded Holocaust Memorial Day, has called Jobbik "the most powerful outwardly fascist political party in Europe".
Speaking outside Holborn station, Mr Dismore said: "I think it's very important to send the message that we won't have hatred spread on our streets of London by the Hungarian Jobbik party.
"We have laws here against the incitement of race hatred. Jobbik party is a racist party which targets Roma, it wants to segregate them into ghettos, and it targets Jewish people.
"This is so reminiscent in Hungary of what happened in Nazi Germany in the 1930s and it should not be allowed to continue in the UK, particularly on the eve of Holocaust Memorial Day."
Mr Dismore said the Home Secretary had made "a grave mistake" by not acting on a petition with more 14,000 signatures which called for Mr Vona to be excluded from the UK.
Mr Vona and his party are said to have close links with groups such as the neo-Nazi Golden Dawn party in Greece and the far-right BNP led by Nick Griffin.
Unite Against Fascism (UAF) had urged all anti-fascists and anti-racists to join the protest and oppose any link-up of far-right parties across Europe.
The organisation's joint national secretary, Sabby Dhalu, said: "UAF has played a central role in driving back fascism in Britain. Jobbik's fascist hatred has no place in a modern society here, or in the rest of Europe.
"Wherever fascists have a presence, racist, anti-semitic and Islamophobic attacks increase."
Mr Vona has previously denied claims he planned to meet members of Greece's Golden Dawn party - who have openly expressed admiration for Adolf Hitler - and the BNP today.
His spokeswoman said he planned to host a forum for Hungarian citizens ahead of a forthcoming election.
She said that the claims were "false", adding: "He has no intention of meeting anyone from Golden Dawn or the British National Party.
"This is a forum for Hungarian citizens. This is not to do with anyone else.
"There are lots of Hungarians living in London and the election is coming up in Hungary."
Earlier this month Mr Griffin told reporters that the BNP was likely to forge an alliance with Jobbik and Golden Dawn after the European Parliament elections in May.
Mr Griffin travelled to Athens to support Golden Dawn - which has seen a surge in popularity during the country's financial crisis - following accusations it is a criminal organisation.
Nick Lowles, chief executive of anti-fascist pressure group Hope Not Hate, said: "Sadly the Home Secretary Theresa May has failed to ban the noted extremist leader, Gabor Vona, from the shores of the UK.
"That he should be arriving on the eve of Holocaust Memorial Day, when his party and its politicians have open and disgusting antisemitic views, is all the more deplorable."
A Metropolitan police spokesman said: "We were advised that the event at Camden has been cancelled."
He added that the event had not been cancelled the request of police.
Mr Vona later addressed more than 100 Jobbik supporters gathered in London's Hyde Park.
A Scotland Yard spokesman said: "Police assisted the group to assemble for purposes of lawful protest at an alternative location in order to prevent a possible breach of order."
No arrests were made, he added.