Nick Clegg was left red-faced after being forced to withdraw comments in which he branded opponents of gay marriage "bigots".
The Deputy Prime Minister was expected to launch an outspoken attack on opponents of the policy in a speech at a reception.
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, insisting an early draft had been released in error.
The revised version 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 Mr Clegg 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."
Tory backbencher Peter Bone said Mr Clegg had insulted "millions of people with deep convictions of religion and conscience". He insisted the Lib Dem leader had to "apologise profusely" or resign.
He said: "I don't see how that could have got published without it being the view of the Deputy Prime Minister. He has got to rapidly get out there on the airwaves apologising.
"It is clear what he thinks. There is no way that the Deputy Prime Minister of our country can be associated with that language."
Gay rights campaigner Peter Tatchell, among guests at the reception, said: "It is pretty clear that some people oppose marriage rights for gay people because of deep-seated homophobic bigotry. Nick Clegg should not be afraid to say so."