Gordon Brown finally said sorry yesterday for the plan to smear senior Conservatives which forced the resignation of his close aide Damian McBride.
But as the Cabinet met in Glasgow, some ministers expressed concern that Mr Brown had prolonged the controversy by refusing to issue a personal apology for six days.
“He should have killed this off at the start by saying sorry. It has not been handled well,” one said.
On Monday, the Prime Minister said the affair was “a matter of great regret”, angering the Tories by declining to say sorry or accept responsibility. But yesterday he bowed to the inevitable, saying: “I am sorry about what happened.”
He said he had been “horrified” and “very angry” when he first learned about the emails between Mr McBride and Derek Draper, founder of the LabourList website, which discussed plans to run false allegations about Tories on a proposed gossip site, RegRag.
“I take full responsibility for what happened. That's why the person who was responsible went immediately,” he added.
Mr Brown said he wanted to reassure the public that everything was being done to clean up politics in Westminster: “The person who was responsible went immediately and lost his job and I have ensured that there are new rules so this can't happen again. We have done everything in our power to deal with this.”
George Osborne, the shadow Chancellor, and one of those Labour planned to target, welcomed Mr Brown's words but said: “It has come a little late this apology and it is a shame we had to ask for it.”
He added: “I wish this whole thing had never happened, that is a statement of the obvious. But it did and the Prime Minister has at last, many days later, admitted full responsibility for it.
“That is fine; people will draw their own conclusions about the kind of Government he runs.”
Yesterday Mr Draper issued a personal apology to the Tories who he had discussed targeting with Mr McBride.