A Dutch MP who called the Koran a "fascist book" says he still plans to travel to the UK despite being banned on public security grounds.
Freedom Party MP Geert Wilders was invited to show his controversial film - which links the Islamic holy book to terrorism - in the UK's House of Lords.
But Mr Wilders, who faces trial in his own country for inciting hatred, has been denied entry by the Home Office.
He plans to fly into Heathrow later, saying: "Let's see what happens."
Mr Wilders was asked to show the film at the House of Lords by UK Independence Party peer Lord Pearson.
However, he received a letter from the British Embassy in the Netherlands telling him he would not be allowed into the UK.
Lord Pearson said he disagreed with Mr Wilders' call to ban the Koran, but accused the Home Office of "appeasing violent Islam".
"We're coming to this from the angle of freedom of speech," he said. "This man must be allowed to say what he wants, he must answer questions and then everyone can make up their minds.
"I think this man is raising one of the most important issues of our time. I think it should be discussed more, particularly by the vast majority of the mild Muslim community. They should talk about what the Koran really means.
"These people are using verses in one of the great religious tracts in history to blow up innocent people. That's what we want to talk about... whether these acts of violence can be rooted in the Koran."
Mr Wilders' film Fitna caused outrage across the Muslim world when it was posted on the internet last year.
Its opening scenes show a copy of the Koran followed by footage of the 9/11 attacks in the US and the bombings in Madrid in 2004 and London in 2005.
The Dutch prime minister has said the film served "no purpose other than to offend".
The Home Office said there was a blanket ban on Mr Wilders entering the UK under EU laws enabling member states to exclude someone whose presence could threaten public security.
"The government opposes extremism in all forms," it said in a statement, adding that it had tightened up rules on excluding those engaging in "unacceptable behaviour" in October.
"It will stop those who want to spread extremism, hatred, and violent messages in our communities from coming to our country."
The home secretary has the power to stop people entering the UK if she believes there is a threat to national security, public order or the safety of UK citizens, but she cannot exclude people simply because of their views.
Mr Wilders described the decision as "cowardly" and said he still intends to travel to the UK on Thursday to take part in the event.
He told the BBC: "It's incredible that an elected politician who was invited by one of your parliamentarians to a discussion with people who are against me, or in favour of me [was banned from the UK]."
Mr Wilders added: "I was surprised and very saddened that the freedom of speech that was a very strong point of UK society has been harassed. I thought Great Britain had the mother of all parliaments."
The Dutch government is reported to be trying to overturn the ban and Lord Pearson said the screening would still go ahead on Thursday - with extra security - whether Mr Wilders was present or not.
The peer also called for a major Muslim conference to discuss the Koran and its meaning.
Earlier this year, a Dutch court ordered prosecutors to put Mr Wilders on trial for inciting hatred and discrimination by making anti-Islamic statements.
Labour peer Lord Ahmed, who expressed his concerns to the Parliamentary authorities about Mr Wilders' visit, said he welcomed the decision to ban the MP.
"It would be unwise to have him in the UK because this man's presence would cause hatred," he said.
"He has a case against him in the Amsterdam court for inciting hatred."
Lord Ahmed, who said other Muslim peers shared his concerns, stressed that Mr Wilders' views would certainly present a threat to public order.
The Muslim Council of Britain said Mr Wilders was "an open and relentless preacher of hate".
"We have no problem with the challenge of criticisms to our faith, but the film... is nothing less than a cheap and tacky attempt to whip up hysteria against Muslims," it said.
And Chris Huhne, Lib Dem home affairs spokesman, said he had watched the film, which he called "revolting", and backed the ban.
"Freedom of speech is our most precious freedom of all, because all the other freedoms depend on it," he said.
"But there is a line to be drawn even with freedom of speech, and that is where it is likely to incite violence or hatred against someone or some group."