One of David Cameron's MEPs and close friend of the controversial Polish politician at the centre of a row over anti-Semitism has sparked fury by claiming that homophobia does not exist.
Roger Helmer, Conservative MEP for the East Midlands, said that homophobia was "merely a propaganda device designed to denigrate and stigmatise those holding conventional opinions".
Writing on his aptly named blog Straight Talking, Mr Helmer defended Michal Kaminski, the head of the European Conservatives and Reformists group, who is under fire over his controversial views.
It follows a row over Mr Kaminski's one-time membership of the far-right National Rebirth party (NOP) and his opposition to an apology for Polish involvement in a wartime massacre of Jews in the town of Jedwabne.
The Foreign Secretary, David Miliband, last week criticised Mr Cameron for aligning himself with the Polish politician. Mr Kaminski denies that he is anti-Semitic.
However, his Polish Law and Justice Party opposes gay marriage and has banned gay rights marches.
On his blog, Mr Helmer defended the views of his "good friend" Mr Kaminski. The Tory MEP also described himself as "liberal and tolerant on the question of homosexuality", but said he was opposed to the concept of gay marriage on "semantic and social policy grounds".
He added: "'Homophobia' is merely a propaganda device designed to denigrate and stigmatise those holding conventional opinions, which have been held by most people through most of recorded history.
"It is frightening evidence of the way in which political correctness is threatening our freedom.
"It is creating 'thought crimes', where merely to hold a conventional opinion is seen, in itself, to be unacceptable and reprehensible. I'm sorry, but I don't buy it."
His words were posted last month but came to light yesterday, as the row over Mr Kaminski escalated.
The remarks will cause concern among members of Mr Cameron's inner circle who are alarmed that the row is casting his European policy in an unflattering and backward-looking light.
Ben Summerskill, the chief executive of Stonewall, said yesterday: "If Mr Helmer thinks that homophobia doesn't exist in modern Britain, then perhaps he should be introduced to the families of Michael Causer and Jody Dobrowski. I suspect that their dignity in the face of the murders of their sons by homophobes might cause Mr Helmer to think again.
"The sort of delusional paranoia he expresses seems to be precisely the same as the hysteria that led some of his colleagues in the 1980s to bequeath the Conservative Party the millstone of Section 28. If they have any sense, they will not give him the oxygen of further publicity."
Geoff Hoon, former chief whip and ex-Europe minister, said: "This is yet another sign that David Cameron has caved in to the views of the extreme elements in his party and removed the Conservatives from Europe's mainstream.
"Some of David Cameron's new allies on the fringes of Europe are seemingly happy with making homophobic comments, but the Tory leader now needs to say if he agrees with his own MEP that homophobia is merely 'conventional opinion'."
Mr Helmer was one of the outspoken figures on the Tory right who pressed Mr Cameron to keep his promise, made in 2005 to win over Eurosceptics, to withdraw from the mainstream in Europe.
He was thrown out of the Conservative European People's Party grouping in 2005 for organising a Better Off Out campaign, but the Tory whip was later reinstated. He was a leading proponent of the Tories' decision to withdraw from the EPP and create the new grouping.
Mr Helmer is honorary chairman of the right-wing Freedom Association and a climate-change sceptic.