Protesters have begun to gather outside the Oxford Union where historian David Irving and BNP leader Nick Griffin will speak later tonight.

Both are due to take part in the Union's free speech forum, but it has sparked controversy over whether the pair should be given a platform.

Around ten coachloads of anti-facist protesters from around the country are due to arrive at 7pm.

But many have already gathered outside the Union, in St Michael's Street, ahead of the controversial debate.

Representatives from Unison were joined by campaigners from Unite, as well as Jewish and Muslim groups.

Weyman Bennett, of Unite Against Fascism, said: "It's up to the good people here to stand together against fascism and say we don't want in this or any country."

Student rabbi and Oxford Union member David Mitchell said: "It's utterly horrendous. I can't believe Oxford Union is giving creditability to these people and I will be resigning my membership in the morning."

Home Secretary Jacqui Smith told the Commons earlier today it was up to the debating society to make its own decision about allowing Mr Irving and Mr Griffin to attend the freedom of speech event.

Ms Smith, an Oxford graduate, said in Home Office Questions: "I thoroughly deplore the sentiments, the expressed views and the actions of both of the gentlemen due to be speaking at the Oxford Union society this evening."

She said there was legislation which she hoped would be used if they "overstepped the mark".

Conservative frontbencher Julian Lewis, MP for New Forest East, resigned his life membership of the Oxford Union in protest at the decision to invite the pair to speak.