British National Party leader Nick Griffin has used his Question Time appearance to criticise Islam and defend a past head of the Ku Klux Klan.
He also told a largely hostile audience that Winston Churchill would be a BNP supporter if he were alive, and said he would find two men kissing "creepy".
Anti-fascist protestors scuffled with police outside BBC TV Centre in west London before the show was filmed.
Minister Peter Hain said the BBC had legitimised the BNP's "racist poison".
But the corporation defended the invitation to the leader of the anti-immigration party to appear, saying it had a duty to be impartial.
One of the panellists, Justice Secretary Jack Straw, said it had been a "catastrophic week for the BNP because for the first time the views of the BNP have been properly scrutinised".
And following the programme, other panellists said Mr Griffin had been exposed.
Baroness Warsi, the Conservative peer and shadow communities minister, said "he does not have any political views other than a hatred for certain groups of people".
Liberal Democrat home affairs spokesman Chris Huhne said: "I certainly think that his credibility - for anybody who sees the show - is going to be seriously damaged by his performance."
Mr Griffin told BBC News too much of the programme had been a "beat up Nick Griffin programme instead of Question Time".
He added that of the 25 or so allegations made against him in the programme - he was only allowed to answer four or five of them and that was "grossly unfair".
'Aborigines here'
The BNP leader was booed at the start of the recording and accused of trying to "poison politics" as he was attacked by fellow panellists and the audience.
During the show the panel covered topics including whether it was fair for the BNP to "hijack" images of Winston Churchill, whether immigration policy had fuelled the BNP's popularity and whether Mr Griffin's appearance was an early Christmas present for the party.
He was asked by a member of the audience about why he had described Islam as a "wicked and vicious faith".
Mr Griffin said the religion had its "good points... it wouldn't have let the banks run riot" but it did not fit in with "the fundamental values of British society, free speech, democracy and equal rights for women".
His references to Britain's "indigenous people" prompted other members of the panel to challenge him to say he meant white people.
Mr Griffin said the colour was "irrelevant" and said Mr Straw would not dare go to New Zealand and tell a Maori he was not "indigenous". "We are the aborigines here," he claimed.
Mr Straw said what distinguished the BNP from other parties was that other parties "have a moral compass... Nazism didn't and neither I'm afraid does the BNP."
Mr Griffin said his father had been in the RAF during World War II and added he had been "relentlessly attacked and demonised... I am not a Nazi and never have been".
Mr Griffin repeatedly denied he had said many of the things attributed to him including a Mail on Sunday quote that Adolf Hitler went "a bit too far".
He claimed his efforts to change the BNP meant he was unpopular with the far right. "There are Nazis in Britain and they loathe me," he said.
He admitted sharing a platform with former Ku Klux Klan leader David Duke - but described him as "almost totally non-violent".
He said he had been trying to win over "youngsters" Duke was trying to "lead astray".