OXFORD'S police chief has warned troublemakers to stay away from a demonstration against the BNP tonight.

BNP leader Nick Griffin and Holocaust denier David Irving have been invited to speak at Oxford Union's Free Speech Forum.

The invitations have sparked huge controversy, with opinions across Oxford divided on whether the pair should be given a platform to speak at the prestigious event.

One Oxford city councillor claims to have been threatened with violence because of his outspoken views on the subject.

More than a thousand protesters - including members of Unite Against Fascism and Oxford University Students' Union - are expected to descend on St Michael's Street in the city centre tonight at 8pm to demonstrate against the invitations.

About 100 people who support the invitations - including members of one of Oxford's largest Muslim community groups - will also stand outside the event to show their support for free speech.

Supt Brendan O'Dowda yesterday warned the opposing factions they had a right to protest but no-one should turn up if they were going to cause trouble.

He said: "We will facilitate lawful protest as far as possible and police those both for and against with sensitivity.

"But do not turn up - whether you are for or against - if you are hellbent on causing trouble, because you will be dealt with."

Unite Against Fascism national secretary Weyman Bennett last night stressed their demonstration against the invitations would be peaceful.

He said: "It is a bit like putting a paedophile on a platform and saying we know the paedophiles are wrong but we are going to glorify this person."

Green city councillor David Williams claimed he received an anonymous threat on Friday morning, after speaking out against publicising the speeches.

He said he had contacted police. He said the caller had left an aggressive message on his answerphone. He added: "They said they are going to kick my head in because I'm left wing."

Dr Taj Hargey, chairman of the Muslim Educational Centre of Oxford (MECO), said he supported the invitations.

He said about a dozen members of the MECO would campaign outside the forum for Mr Griffin and Mr Irving's right to speak.

Dr Hargey said: "Either there is free speech for everyone or there is free speech for no one.

"We feel strongly that free speech is integral to Islam and all opinions should be expressed with the proviso that alternative opinions are heard."

A BNP spokesman said Mr Griffin would be accompanied by a small security team, and added: "If there are clashes it will be clashes between the left wing and the police."

Mr Irving, who was jailed in Austria for denying the Nazi execution of millions of Jews, said: "I have not been intimidated before and I do not think I will be intimidated this time.

"I'm very pleased I will have the opportunity to speak at the Oxford Union. I was convinced that the enemies of free speech would prevent me speaking."

Charlie Holt, spokesman for the Oxford Union, said: "We have got tight security and we will be co-operating closely with the police."