Nick Clegg has become embroiled in a row over gay marriage after aides had to remove comments in the draft version of a speech calling opponents "bigots".
The deputy PM was expected to launch an attack on those against the policy - which include some Tory MPs - in a speech at a reception in London.
But the wording of initial extracts released to the media was changed.
Mr Clegg later insisted he never intended to use such language as it was "not the kind of word" he would use.
Sources close to Mr Clegg said the "bigot" claim was "a mistake" in an early draft of the speech which should not have been released to the press.
But Former Archbishop of Canterbury Lord Carey said the remarks were "very offensive".
"If he persists in taking that view I and others would be very offended, he said.
"To be called a bigot is a very offensive statement and I would ask him to recall it...because there are issues here that demand very serious debate."
Extracts released early by officials said: "Continued trouble in the economy gives the bigots a stick to beat us with, as they demand we 'postpone' the equalities agenda in order to deal with 'the things people really care about'."
Within an hour aides had corrected the text, which said: "Continued trouble in the economy leads some people to demand we 'postpone' the equalities agenda in order to deal with 'the things people really care about'."
A spokesman for the deputy PM said: "This was not something the deputy prime minister has said. It is not something he was ever going to say, because it is not something that he believes.
"It was removed from the draft copy, that should never have been sent out, for that very reason."
Mr Clegg later addressed the issue at the event in central London, attended by celebrity campaigners and religious figures who back legalising gay marriage.
"I am a little bit surprised to see cameras assembled outside the gates, for the slightly obscure, surprising reason that they expect me to use a word about opponents of gay marriage that I had no intention of using, would never use," he said.
"It is not the kind of word that I would use."
While he "stridently disagreed" with those opposing the legalisation of gay marriage, Mr Clegg said he would "never seek to engage in debate in insulting terms".
The BBC's chief political correspondent Norman Smith said the incident was likely to "incense" many Conservative MPs.
'Not fit and proper'
Conservative MP Peter Bone - who has repeatedly called for the coalition to be broken up - said if Mr Clegg believed what was said in the original draft of the speech, he was not a "fit and proper person to be deputy prime minister".
"Nick Clegg has got to explain himself and apologise very rapidly," he told the BBC News Channel.
"This is not the way the deputy prime minister behaves."
The campaign group Coalition for Marriage, which opposes any change to the law, described the remarks as "intolerant".
"It also shows his contempt for the millions of ordinary men and women in this country who oppose the politically correct drive to rip up the centuries old definition of marriage," its campaign director Colin Hart said.
But gay rights campaigner Peter Tatchell said Mr Clegg "should not be afraid" to raise the issue of prejudice within the context of the debate on gay marriage.
"It is pretty clear that some people oppose marriage rights for gay people because of deep-seated homophobic bigotry," he said.
Since 2005, same-sex couples have been able to enter into civil partnerships, which confer broadly similar rights and responsibilities to married couples.
However, at the moment, only a man and a woman can be legally married.
The UK government has completed a consultation on proposals that could see gay marriage being legalised in England and Wales and enable existing civil partners to "convert" into a civil marriage.
Under the proposals, religious organisations would not be obliged to conduct same-sex marriages in their places of worship and there would be no change to how religious marriages are solemnized.
Prime Minister David Cameron, Mr Clegg and Labour leader Ed Miliband are all in favour of the change but the Church of England and other religious organisations have expressed serious concerns about its impact on the institution of marriage and the role of the Church in society.
The Scottish government has said it will seek to legislate to introduce gay marriage by 2015, which has sparked a fierce row with the Roman Catholic Church in Scotland.