David Cameron told a meeting of Conservative MPs in Westminster on Monday that he had "called the bluff" of Ed Miliband during negotiations over the future regulation of the press, it has been reported.
The Conservative Party and Labour Party have been battling to claim victory in the last minute talks that resulted in a deal in the early hours of this morning, avoiding a showdown vote in the Commons.
Downing Street has insisted the deal, that will see newspaper regulation backed up by a royal charter, avoids the statutory underpinning that Cameron rejected as a danger to the freedom of the press.
However the Labour Party has insisted the amendement to law necessary to bring in the new system is statutory underpinning, as recommended by Lord justice Leveson, and therefore closer to its position.
According to the Press Association, interventions at the gathering of Tory MPs were said to have been generally positive, with Nadhim Zahawi describing the deal as "the right thing to do" and George Eustice is said to have insisted there was "no point taking entrenched positions" on the issue.
A Downing Street source admitted that some questions were raised about the agreement, with one MP asking whether the party had "dipped our toe in the Rubicon".
Another party source said the prime minister had put a "final idea" to Miliband and Nick Clegg nine hours before they responded that they were ready to discuss it.
Former minister Jonathan Djanogly was said to have asked at the meeting this afternoon why the process had been so secretive.
The source played down the importance of Cameron's absence from the talks, saying Cabinet Office minister Oliver Letwin had been acting on his behalf and to his instructions.
Cameron was in contact with Letwin by telephone, and did not go to bed until 3.20am - after the negotiations had wrapped up for the night. Cameron was then up at 6am for a conference call with Letwin on the issue.
Tory backbencher Angie Bray said she had told the prime minister he had "extracted the best he could out of a very difficult situation".
But she also warned that he had "dipped his toe in the rubicon".
"I think probably it was the only reasonable compromise that leaves all three political parties able to feel that they have kept something that they hold important," she said afterwards.
"But I did say in the meeting... that while I congratulated the PM on not having to cross the rubicon lock stock and barrel, he did have to dip his toe in the rubicon.
"There is a statutory element to it, albeit as mild as you can get. I believe the prime minister has extracted the very best that he can out of a very difficult situation."
The former ministerial aide added: "I just have to hope that it isn't a slippery slope."
Some Tory MPs have expressed frustration at having supported the prime minister's opposition to any form of statutory underpinning only to wake up this morning to find a deal had been done.