A plane carrying Geert Wilders, the rightwing Dutch politician accused of Islamophobia who is banned from entering the UK, touched down in London today.

Wilders was due to show his 17-minute film Fitna, which criticises the Qur'an as a "fascist book", at the House of Lords today but on Tuesday he received a letter from the Home Office refusing him entry because his opinions "threaten community security and therefore public security".

The controversial leader of the Freedom party, who arrived at Heathrow airport shortly after 2pm, told the BBC of his plans to travel in contravention of the ban earlier today, saying "Let's see what will happen." He added: "I was very surprised and very saddened that the freedom of speech that I believe was a very strong point in UK society is being harassed today."

It is understood that the controversial politician's passport will be flagged up at Heathrow immigration and he will be refused entry to Britain at that point.

Fitna intersperses images of the September 11 attacks with quotations from the Islamic holy book and its release last year sparked violent protests in the Muslim world. In 2007, Wilders called for the Qur'an to be banned and likened it to Adolf Hitler's Mein Kampf. Last month, an Amsterdam court ruled that he should be prosecuted for inciting racial hatred but Wilders has launched an appeal against the decision.

The Dutch foreign minister, Maxime Verhagen, said the Dutch government would press for a reversal of the travel ban on Wilders, and a UK Independence party peer, Lord Pearson, who invited Wilders to Britain, said the screening of the film would go ahead today, whether he was there or not.

Speaking outside the House of Lords today, Pearson said he disagreed with some of Wilders' views but was "coming at this from the angle of free speech". Pearson described the Dutch politician as a "very brave man" and said he did not think he was a racist.

"I think this man is raising one of the most important issues of our time, which is Islamic militarism, which is a violent jihad," said Pearson. "That's the issue that this man is raising, and I think that should be discussed much more, particularly amongst the vast majority of the mild Muslim community."

The peer initially said he did not believe there should be any limits to freedom of speech but when pressed conceded that there should be "a very few", such as language that incited violence. Pearson said he believed a Hitler-type figure should be allowed to speak in public in Britain. "I would go and laugh at him. You couldn't take him seriously, could you?" he said.

The peer revealed he had put down a motion for debate in the House of Lords urging the government to sponsor a conference into whether the Old Testament, New Testament and Qur'an contained justification for violence.

The National Secular Society president, Terry Sanderson, said he wrote to the home secretary, Jacqui Smith, saying she should not have denied an application by a "democratically elected politician from a sovereign state who wants to come and express an opinion".

"It may be a controversial opinion but he is entitled to express it," he said.

The Home Office has said it would "stop those who want to spread extremism, hatred and violent messages in our communities from coming to our country".

A spokesman for the Muslim Council of Britain described Wilders as "an open and relentless preacher of hate".

"We have no problem with the challenge of criticisms to our faith, but the film that will be screened by Lord Pearson and Baroness Cox is nothing less than a cheap and tacky attempt to whip up hysteria against Muslims," he said.

The Liberal Democrat home affairs spokesman, Chris Huhne, said that while it was important to defend freedom of speech, Wilders "has overstepped the line that should be defended in a civilised society".

Wilders said he had already shown his film to Denmark's parliament and intended to take it to Italy and the US House of Representatives in the coming weeks.