David Cameron's hopes of putting a lid on the phone-hacking scandal were foundering on Wednesday after he was forced to concede he had talked to Rupert Murdoch's executives about their bid to take control of BSkyB.

It is the first time he has made the admission, but he insisted the conversations had been "appropriate" because he did not convey any of those discussions to the politician in sole charge of handling the bid, the culture secretary, Jeremy Hunt.

Cameron also came close to an apology over his decision to appoint Andy Coulson as No 10's director of communications, admitting with hindsight he should not have offered him the job.

Making an exhaustive 139-minute emergency statement to MPs, he edged towards the much-demanded apology about Coulson: "Of course I regret, and I am extremely sorry, about the furore it has caused. With 20/20 hindsight, and all that has followed, I would not have offered him the job, and I expect he would not have taken it."

He added: "I have an old-fashioned view about innocent until proven guilty, but if it turns out that I have been lied to, that would be the moment for a profound apology. In that event, I can tell you that I will not fall short."

The Labour leader, Ed Miliband, said it was not about hindsight. Cameron had ignored five warnings of Coulson's activities, he said, including a damning article by the New York Times in September 2010 that prompted major changes at the Metropolitan police, but not in Downing Street. Cameron repeatedly tried to avoid admitting he had discussed the BSkyB deal at one or other of the 26 meetings he has held with Murdoch's executives since the election.

Faced by repeated Labour questioning, he said he had not had any inappropriate conversations about BSkyB with Murdoch's executives.

He said there was not a single conversation that could not have taken place in front of a select committee, a phrase first used by the former News International chief executive Rebekah Brooks on Tuesday.

Hunt went further in admitting the conversations between Cameron and Brooks, saying: "The discussions the prime minister had on the BSkyB deal were irrelevant. They were irrelevant because … the person who was making this decision was myself. I was making it on my own. This was not a matter of collective responsibility, this was a quasi-judicial process."

Later, Cameron's aides said the prime minister could not prevent company executives lobbying him in meetings. They added that the cabinet secretary, Sir Gus O'Donnell, had said the discussions did not breach the ministerial code.

But Cameron's admission that he held such discussions arguably gave News Corp a commercial advantage in that it would help inform the company's representations to the culture secretary.

The shadow culture secretary, Ivan Lewis, said: "Despite claiming he was prepared to answer 'any and all' questions, he still hasn't given full details on these meetings, including when they took place and what exactly was discussed. Cameron needs to come clean and provide complete transparency. Until he does so, there will continue to be serious questions about his judgment."

Cameron implicitly admitted there was a problem about any ministerial involvement in the BSkyB takeover bid. "I think that there might be a case, when it comes to media mergers, for trying further to remove politicians." He added: "We should be frank: sometimes in this country, the left overestimates the power of Murdoch, and the right overdoes the left-leanings of the BBC. But both have got a point, and never again should we let a media group get too powerful."

Nick Clegg, the deputy prime minister who has struck a defiantly independent tone during the crisis, will hold his first solo press conference on Thursday in a sign of his determination not to be dragged into the mire with Cameron. Clegg advised against the appointment of Coulson last year, and Chris Huhne, his home affairs spokesman in opposition, was approached by the Met to lay off criticisms of the way they had conducted their inquiries.

But Conservatives are hoping the start of the long parliamentary recess and the finalisation of the judicial inquiry into the hacking will see the feverish energy surrounding the scandal finally dissipate as the public focuses on the economy and the euro crisis. Conservative strategists sense scandal exhaustion has crept in, even if Labour claimed Cameron was heading for the beaches with a cloud over him.

An Ipsos MORI poll showed the recent furore had left Cameron's personal satisfaction ratings at their lowest point since he became prime minister, and lower than any of his ratings as leader of the opposition since September 2007.

As Rupert Murdoch left the UK on a private jet, his executives were still moving slowly to end any remaining signs of a cover-up over the wrongdoing.

News Corporation terminated arrangements to pay legal fees of private investigator Glenn Mulcaire "with immediate effect". It also instructed solicitors Harbottle & Lewis that it was released from a confidentiality agreement that prevented it from telling the police how it had come to write a wholly inaccurate letter to the culture select committee in 2007 insisting the phone hacking and illegal activities had been confined to a sole reporter.

In hindsight

John Yates: "I should have cogitated and reflected, but it's so bloody obvious there was nothing there [that we didn't already know]. I didn't do a review. Had I known then what I know now – all bets are off. In hindsight there is a shed load of stuff in there I wish I'd known."

James Murdoch: "So if I knew then what we know now and with the benefit of hindsight we can look at all these things, but if I knew then what we know now we would have taken more action around that and moved faster to get to the bottom of these allegations."

David Cameron: "Of course I regret, and I am extremely sorry about the furore it has caused. With 20/20 hindsight and all that has followed I would not have offered him [Coulson] the job and I expect that he wouldn't have taken it. But you don't make decisions in hindsight, you make them in the present. You live and you learn and believe you me, I have learned."

Sir Paul Stephenson: "As commissioner I carry ultimate responsibility for the position we find ourselves in. With hindsight, I wish we had judged some matters involved in this affair differently. I didn't and that's it."