Peter Clarke, who headed the force’s counter-terror division, said there was “scepticism” in the media that the capital was a target before the 7 July attacks.
The retired assistant commissioner told the Leveson Inquiry into press standards that he met Mr Murdoch and held separate meetings with other media bosses in August 2004.
Lord Stevens - the then commissioner - had been “appalled” by the threat of a dirty bomb, he said.
“He directed that he and I should visit the whole range of media outlets, not just News International,” Mr Clarke told the inquiry.
There was a “considerable amount of scepticism about the reality of the terrorist threat in the UK”, he added.
When asked why he met media organisations for food, he said “it was felt it would be useful to have more informal meetings from across media outlets”.
“My sense was that the support was being undermined by some of the negative comment in the media,” Mr Clarke told the inquiry.
“The purpose was not to make the police look good, but to try and balance the public discussion, so that communities could have confidence in the integrity of what we were doing.”
He added: “I was not interested in trying to make the police look good.”
Mr Clarke rose from deputy assistant commissioner to assistant commissioner as he headed Scotland Yard’s counter-terror branch between 2002 and 2008.
When asked about the relationship between police and media, he said that “in my experience, there’s no such thing as an overall culture”.
“Even within Scotland Yard, different departments, different people dealt with the media in different ways, and so I can’t identify an overall culture,” he said.