Nick Griffin is complaining he had faced a 'lynch mob' on Question Time
Former Archbishop of Canterbury Lord Carey has urged Christians to "stand shoulder to shoulder" in rejecting the British National Party.
He told the News of the World the party's leader was a "squalid racist".
It was "chilling" to hear Nick Griffin claim to represent "Christian Britain" on BBC One's Question Time, he added.
Lord Carey said the other panellists should have challenged him more on his "deceitful attempt to align his despicable policies with Christianity".
In the newspaper interview, Lord Carey accused the BNP leader of trying to "hijack one of the world's great religions" and said the decision to invite him on to the BBC's flagship political discussion programme had been "a mistake".
The BBC has handed the BNP the gift of the century on a plate
Welsh Secretary Peter Hain
"To hear the phrase 'Christian Britain' coming from the mouth of Nick Griffin made me shudder. It was the most chilling moment of Question Time, perhaps better described as the Nick Griffin Show," he said.
He called on "all Christians to stand shoulder-to-shoulder in rejection of Griffin's notion that 'Christianity' has any place in his bigotry".
Lord Carey said other parties needed to deal with the issue of immigration in a balanced and firm way or the BNP would "feed off the anger of citizens of all races and religions".
"A controlled approach to immigration is needed with clear caps set on population growth," he added.
A News of the World poll of 504 people suggested two-thirds of people felt the mainstream parties had no credible policies on immigration.
The ICM research was based on interviews with a random sample of adults on 23 and 24 October.
Mr Griffin, who was one of two BNP candidates to be elected to the European Parliament earlier this year, faced robust questioning about his views on race, immigration and the Holocaust from a largely hostile audience on Question Time on Thursday.
He criticised Islam and defended a past head of the Ku Klux Klan but insisted that he was "not a Nazi".
His fellow Question Time panellists said he had been "shown up" but the BNP claims 3,000 people registered to join the party during and after the broadcast, which was watched by a record eight million viewers.
Mr Griffin has since said he plans to complain to the BBC as he had faced a "lynch mob".
He said the normal format of Thursday's programme had been changed and it should not have been held in London, which he said was "no longer a British city" because of the levels of immigration.
More than 240 complainants to the BBC felt the show was biased against the BNP, while more than 100 complaints have been about Mr Griffin being allowed to appear on Question Time in the first place.
However, more than 50 people contacted the BBC to show their appreciation for the programme.
BBC Deputy Director General Mark Byford defends Question Time
A YouGov poll reported in the Daily Telegraph on Saturday suggested support for the BNP had risen after Mr Griffin's appearance on the show.
The poll suggested 22% of people questioned would consider voting for the BNP in a future local, general or European election.
The findings sparked anger among opponents of the BNP. Welsh Secretary Peter Hain said: "The BBC has handed the BNP the gift of the century on a plate and now we see the consequences. I'm very angry."
Meanwhile, Sunday is the deadline for Mr Griffin to have signed the court order agreeing to the BNP voting on changing its constitution so it does not discriminate on grounds of race or religion.
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