The People, using extensive quotes, apparently from Mr Mellor himself, from what appear to be private conversations with Antonia de Sancha, was described as 'sneaky' by Geoffrey Dickens, the Tory MP. There was also speculation about whether bugging devices were used.
Bill Hagerty, the editor of the People, said: 'The story involving Mr Mellor has been obtained legitimately. This newspaper has tapped no phones. If a Cabinet minister has a relationship which even he admits is interfering with his function as a Cabinet minister . . . it is a matter of public interest.' He denied that the story was a 'kiss-and-tell buy-up'.
Today, the People's sister paper, the Daily Mirror, reports that tape recordings of telephone conversations between Ms de Sancha and Mr Mellor were made without their knowledge. It also reports that Mr Mellor used to meet Ms de Sancha at a flat belonging to Nick Philp, a friend of the actress, who is an electronic alarms expert.
Yesterday, the People said it tracked Mr Mellor to a flat in Chelsea, west London, where he met Ms de Sancha on 6 July. It was reported that he arrived at 10.58pm and left at 7.55 the next morning. A quote from Mr Mellor to Ms de Sancha in the report says: 'You have absolutely exhausted me. I feel seriously knackered. I had a wonderful time with you last night and I've felt really positive all day . . . I've got two big speeches to do tomorrow, neither of which I have prepared.'
But, if the People is to be believed, it was aware that the story would have to be highly detailed and expansive to take on a senior politician who knows how to deal with the press.
One portion of the report contains an alleged account of how Mr Mellor tutored Ms de Sancha on coping with the press. He apparently said: 'You see, what we choose to do when we're alone is a matter for us and people can only blow us away if one of us betrays the situation or if we are caught in a situation so obvious and flagrant that no denial is possible.'
Other alleged advice included: 'Now remember the golden rule is nobody needs to have a conversation with a journalist. All you have to say is, 'I'm amazed you've had the cheek to call me' or 'I don't know what you're talking about, I'm not participating in this conversation'. Bang] Put the phone down.'
Mr Mellor is also alleged to have consulted with the investigative journalist Paul Halloran on whether anything linking him with the actress would be published.