Downing Street today denied claims that it was responsible for leaking an internal e-mail to the press in an attempt to jeopardise Scotland Yard's cash-for-honours investigation.

Tony Blair's official spokesman said that allegations that No 10 was behind any recent leaks were "just plain wrong".

He spoke as the Attorney General partially lifted an injunction which last Friday stopped the BBC, which had obtained a copy of the memo, running any stories about it.

The media is now officially allowed to reveal that the e-mail had been sent by Ruth Turner, the No 10 director of communications, to Jonathan Powell, Tony Blair's chief of staff, and was about the Prime Minister's chief fundraiser Lord Levy.

However, the press is still banned from revealing any of its details.

Police had applied to Lord Goldsmith for an injunction last Friday to stop any reporting of the e-mail because it feared that revealing all of its details could wreck their investigation.

Some have claimed that Downing Street knew that publicly broadcasting such an e-mail could have wrecked the police's long-running investigation, which is at a sensitive stage.

But Mr Blair's spokesman told reporters at his daily briefing that Downing Street was not responsible for the leaks.

"Suggestions that we leaked or were trying to leak this information are just plain wrong - and that’s not based on my personal hunch, it’s because there are inaccuracies in reports which mean it can’t have come from No 10," he said.

"I can’t get into what those (inaccuracies) are because our approach all the way through is we are against all leaks and speculation.

"We think this is a police investigation which should just be allowed to get on as a police investigation. Leaking in the past has been unhelpful, just as this leak has been unhelpful."

The spokesman added: "I don’t know who leaked this information. I don’t know and it would be wrong for me to speculate in any way."

The Crown Prosecution Service today also denied leaking any information about the investigation.

"The police investigation is still ongoing into the so-called cash-for-honours case," a spokesman said. "Once that investigation is complete, the CPS will review the material in line with the Code for Crown Prosecutors and take decisions.

"We have made it plain previously, and do so again, that the CPS has not revealed any of its deliberations on this case and shall not do so until we have reached decisions. This is despite media reports to the contrary which have appeared over the last two days. When the CPS has made its decisions, they will be announced publicly."

The cash-for-honours inquiry is investigating whether political parties sold places in the House of Lords to wealthy benefactors in exchange for large donations or loans.

It started after four businessmen, who secretly lent the Labour Party a total of £5 million, were nominated by the Prime Minister for peerages. The appointments were blocked by the House of Lords Appointments Commission, the independent body which vets peerage applications.

Ruth Turner, Mr Blair's director of Government relations, was arrested in January on suspicion of conspiracy to pervert the course of justice. Lord Levy, the Prime Minister's tennis partner and close friend, has also twice been arrested as part of the inquiry. Overall, 90 people have been questioned during the investigation, including Mr Blair, who has twice been visited by detectives at Downing Street.

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