Jeremy Hunt wrote to David Cameron to urge him to intervene in favour of News Corporation's bid for BSkyB despite having been warned not to by the civil service, the Leveson inquiry has heard.
On 19 November 2010 the culture secretary told the prime minister that business secretary Vince Cable's decision to refer the bid to regulator Ofcom could leave the government "on the wrong side of media policy".
Just a week earlier, on 12 November, officials at the department of culture, media and sport told Hunt that he should not seek to influence the quasi-judicial decision that rested with Cable.
In his evidence to the Leveson inquiry on Friday, the permanent secretary of DCMS revealed Hunt wanted to send a message to Cable but the department warned him that he should not try to influence decision "nor write to BIS about it".
An internal DCMS email said the legal advice was that Hunt "do nothing" and did "not try to convey thinking to VC (Cable) as he must act quasi-judicially".
The email added that Cable would also be receiving legal advice from his own department not to listen to anything Hunt said and that the business secretary "shows all signs of taking that advice".
Hunt was told that while there was no legal barrier to him talking to Cable he would be "unwise to do so".
Hunt told parliament on 25 April 2012: "I made absolutely no interventions seeking to influence a quasi-judicial decision that was at that time the responsibility of the secretary of state for business."
His November 2010 letter to the prime minister appears at odds with this statement.
In December 2010 Cable was stripped of responsibility for the bid after he was secretly filmed saying he had "declared war" on Murdoch.
The prime minister decided he had shown himself to be biased against News Corporation and handed the job to Hunt - despite being aware Hunt had expressed support for the Murdoch bid.
Stephens told the inquiry that once Hunt assumed responsibility for the bid he was told he must put all previous views about Murdoch or News Corp's opponents to one side and should approach the matter with an "open mind".
"That was, to my observation, the approach he took," he added.
Labour have called for Hunt to resign, claiming he knowingly misled the House of Commons over whether he had sought to influence Cable's decision.