Gordon Brown last night wrote to David Cameron and other Conservatives slurred in a smear campaign orchestrated by a trusted senior aide – but stopped short of issuing an apology.
In an attempt to limit the damage inflicted on him by the row, which led to the resignation of Damian McBride over the weekend, the Prime Minister has written to Sir Gus O'Donnell, the head of the civil service. He asked him to tighten up the code of conduct governing special advisers, who are paid by the taxpayer but act as political advisers to ministers.
Although he stopped short of making a personal apology for the emails, which included invented stories designed to smear members of the Conservative Party, he said they were a "matter of great regret" and has written to the MPs targeted, including the party's leader, David Cameron. Downing Street said the contents of the letters were private, but a Tory source later confirmed they did not contain a personal apology.
Mr Brown moved to counter any suggestion that the emails formed part of a broader smear campaign being orchestrated by his inner circle by stating that no other ministers or special advisers were involved.
"Any activity such as this that affects the reputation of our politics is a matter of great regret to me and I am ready to take whatever action is necessary to improve our political system," he said. "I also think it right to make it a part of the special advisers' contract by asking our political advisers to sign such an assurance and to recognise that if they are ever found to be preparing and disseminating inappropriate material they will automatically lose their jobs."
The code for special advisers, which was drawn up in 2001 after concerns over their growing influence, also piles pressure on Gordon Brown to make a personal apology for the episode. It states: "The responsibility for the management and conduct of special advisers, including discipline, rests with the Minister who made the appointment."
A spokeswoman for David Cameron said the Tory leader welcomed the letter and the fact that he had "finally recognised the gravity of what has been happening in Downing Street". But other senior Tory figures called the reforms of the code of conduct a gimmick. Michael Heseltine said that the rules on special advisers were already very clear and that Mr Brown's call for new measures was a smokescreen designed to hide Labour's embarrassment.
Damian McBride, who advised Mr Brown on political strategy, resigned after he was found to have sent the emails. One of his invented stories suggested that Mr Cameron was suffering from an embarrassing illness. Others involved the Shadow Chancellor, George Osborne, and his wife.
Mr McBride sent his ideas for potential smears to a former aide to Peter Mandelson and Labour blogger, Derek Draper. The emails formed part of the preparations for a new website, Red Rag, designed to attack the Conservatives. The site was never launched. They were published over the weekend after falling into the hands of the blogger Paul Staines.
The Tories still have a list of unanswered questions concerning the emails. Mr Brown's intervention came after the Conservative Party had asked for a thorough investigation into exactly who knew about the emails and the wider role of Government special advisers.
In a separate letter sent to Sir Gus last night, the shadow Cabinet Office minister Francis Maude said: "The emails sent by Damian McBride raise serious concerns about the operation of 10 Downing Street and the degree to which the rules about the role of special advisers are being enforced."
Mr Maude also asked Sir Gus to reveal the involvement of the Cabinet Minister Tom Watson who was mentioned in one of the emails. But Mr Watson hit back yesterday, saying he was also now the victim of a smear campaign and repeated that he had no knowledge of the email exchange between Mr Draper and Mr McBride.
"The bottom line is I feel smeared," he said in a blog post. "I knew nothing about the content of these emails, I did not approve the emails, I did not see the emails, yet people are repeating untruths about me on blogs and on TV stations."
Alan Johnson, the Health Secretary, admitted yesterday that the emails had brought shame on the Government and that the Prime Minster should review the way in which his office was run. He said Mr Brown would want to learn lessons "about his private office and about how things are done in Downing Street".
"I think there is a wider responsibility on all political parties to ensure that having seen over the abyss here of what we could sink into if we are not careful, that we are absolutely doubly sure that we are not going to allow that to happen," he added. He denied the Prime Minister needed to personally apologise for the attacks.
While Mr McBride has now left his post, Mr Draper, who described one of the smear emails as "totally brilliant" upon receiving it, remains an unpaid adviser to Labour on new media. The former Deputy Prime Minister, John Prescott, called on the party to remove him immediately, adding he had been "very disappointed" by the emails.
Brown's letter to O'Donnell: An edited extract
I am writing about the Code of Conduct for Special Advisers, and the proposals I want to make to tighten this up.
I am assured that no Minister and no political adviser other than the person involved had any knowledge of or involvement in these private emails that are the subject of current discussion.
Mr McBride has apologised and done so unreservedly. But it is also important to make sure such behaviour does not happen again. I am ready to take whatever action is necessary to improve our political system.
I would now like a more explicit assurance included in the special advisers' Code of Conduct that not only are the highest standards expected of political advisers but that the preparation or dissemination of inappropriate material or personal attacks have no part to play in the job of being a special adviser.
I also think it right to make it a part of the special advisers' contract by asking our political advisers to sign such an assurance and to recognise that if they are ever found to be preparing and disseminating inappropriate material they will automatically lose their jobs.
I think you will agree that all of us in public life have a responsibility to ensure that those we employ and who are in involved in our parties observe the highest standards.
I entered politics because of a sense of public duty and to improve the lives and opportunities of those less fortunate than me. My undivided focus as Prime Minister is on acting to make Britain a fairer, safer and more prosperous nation and, in particular, on guiding the country through the current economic difficulties.