A Number 10 spokesman said: 'The Prime Minister's line has not changed.' John Major fully backed Mr Mellor, who would remain in office, with responsibility for the press and media.
But Ann Winterton, the first Conservative backbencher to go public with a call for Mr Mellor's resignation, was just the tip of a growing Tory iceberg, and she was joined by one of the most powerful men from the Tory tabloids, Sir David English, chairman and editor-in-chief of Associated Newspapers - the Mail group - who said he did not see how Mr Mellor could carry on.
The Daily Mail, which had hoped on Monday that Mr Mellor might survive, said yesterday: 'David Mellor's position as a Minister of the Crown is untenable.' The Sun carried 'soft' pornographic pictures under the front-page headline, 'Mellor girl's portion from the pizzaman'.
As for the beleaguered Mr Mellor, his department reported that it was 'business as usual'.
Mrs Winterton broke party ranks during a BBC radio interview, in which she said: 'People who go into public life know what the rules are, and know perfectly well that if certain matters are revealed which are embarrassing to them, their families and the Government, sadly they only have one option.'
Even Conservative Central Office was forced to concede: 'Time will tell . . .'
Sir David, the former editor of the Daily Mail and a friend of Mr Mellor's, told BBC radio: 'I think he will go because his position is just impossible . . .He has been moved from a minister for fun, to a figure of fun, to a figure of ridicule, and I just don't think he can continue.' But one of Sir David's own papers, the London Evening Standard, said: 'Mr Mellor should not be obliged to resign because people are making fun of him. He is an able minister.'
Dame Jill Knight, another Conservative backbencher, said: 'If the press, by a concerted attack on a politician - not on the way he does his job, but on something in his private life - can literally hound a man out of office, that has very worrying implications.'
Meanwhile, Peter Bottomley, the Conservative MP who criticised the Independent over a report that Virginia Bottomley had her first child before they married, and gave the child's name, defended the right of newspapers to be wrong and opposed any attempt to 'shackle' them with privacy legislation.
But Sir David Steel, the former Liberal leader, did not believe that the Prime Minister had ever favoured such legislation. 'I've reason to believe, having been in contact with him, that he's not in favour of a Privacy Bill along the lines that have been discussed with him, because he doesn't believe it can be workable,' he said.