Gordon Brown bears personal responsibility for creating the sort of culture that allowed a senior Downing Street aide to consider smearing senior Tories, David Cameron has said.

The Conservative leader, who was among those targeted by Damian McBride, said only a change of government would bring an end to such “nonsense”.

“What this whole episode demonstrates is the need for change. Not change in the special advisers code but change in the culture at Number 10 Downing Street,” he said “I do not think we will get a change in culture until we get a change in leadership and we won’t get a change in leadership until we get a change of government.

“These people have just been in power too long, they have forgotten who they are serving, what they are meant to be doing, how they are meant to behave and we need some change.”

Mr McBride, a close adviser to the Prime Minister for almost a decade, resigned in disgrace after admitting that he sent “juvenile and inappropriate” emails from his Downing Street account to former spin doctor Derek Draper. In the private emails, the two men discussed setting up an “attack blog” called Red Rag that would spread unfounded gossip about Conservative opponents and their families.

Mr Brown denies any previous knowledge of the emails or the website plans but the Tories have asked Cabinet Secretary Sir Gus O’Donnell to launch a full-scale inquiry.

Shadow cabinet office minister Francis Maude said he wanted to find out if ministers knew about the Red Rag website and has specifically asked Sir Gus to investigate whether Cabinet Office Minister Tom Watson MP (West Bromwich East) was aware of the website plans.

At the weekend, the minister denied any knowledge of the emails or any involvement in “discussions to create the Red Rag website”.

The Prime Minister’s spokesman, pressed repeatedly on whether Mr Watson had been aware of the plans, would say only that he had “nothing to add” to Mr Watson’s own statement.

But he said Mr Brown had full confidence in his colleague, who worked close to Mr McBride.

At the weekend the Prime Minister wrote to all those targeted by the stories, which he accepts were all untrue, expressing his “deep regret” over the affair.He also promised to tighten the rules for special advisers but failed to offer the sort of personal apology the victims of the planned smear felt they were owed.

Mr Brown was said by his spokesman to have been “furious” about the emails, the furore over which led to a “huge amount of frustration” in Downing Street that it was overshadowing efforts to get the country out of recession.

Cabinet colleagues have publicly rallied to his support, insisting he could not be held personally responsible.

But other senior Labour MPs said the scandal exposed an unhealthy culture of hostile briefing and a serious need for the Government to focus on policy.

Blairite former ministers Alan Milburn and Stephen Byers said they had both been victims of Mr McBride’s hostile tactics.