TONY BLAIR had to persuade US President George Bush not to launch a military strike on the studios of TV station Al-Jazeera.
New reports claim the two leaders debated an attack on the station which has broadcast video messages from al-Qaida head Osama bin Laden and leaders of the insurgency in Iraq, as well as clips of dead British and US soldiers.
There have been calls for Downing Street to publish the transcript of their conversation.
According to sources it records Mr Bush suggesting that he might order the bombing of Al-Jazeera's studios in Qatar.
And the transcript allegedly details how Mr Blair argued against an attack on the station's buildings in the business district of Doha, the capital city of Qatar, which is a key ally of the West in the Persian Gulf.
It is claimed the transcript records a conversation during Mr Blair's visit to the White House on April 16 last year, in the wake of a failed attempt to root out insurgents in the city of Fallujah, in which 30 US Marines died.
A spokesman for 10 Downing Street refused to discuss the leaked memo.
But former defence minister Peter Kilfoyle - a leading Labour opponent of the Iraq War - called for the document to be made public.
"I believe that Downing Street ought to publish this memo in the interests of transparency, given that much of the detail appears to be in the public domain," he said.
"I think they ought to clarify what exactly happened on this occasion.
"If it was the case that President Bush wanted to bomb Al-Jazeera in what is after all a friendly country, it speaks volumes and raises questions about subsequent attacks that took place on the press that wasn't embedded with coalition forces."
Liberal Democrat foreign affairs spokesman Sir Menzies Campbell added: "If true, then this underlines the desperation of the Bush administration as events in Iraq began to spiral out of control. On this occasion, the Prime Minister may have been successful in averting political disaster, but it shows how dangerous his relationship with President Bush has been."
The document allegedly turned up in the constituency office of former Labour MP Tony Clarke in May last year.
Mr Clarke - who voted against the Iraq War and lost his Northampton South seat in this May's election - returned the document to No 10 because of fears that British troops' lives might be put at risk if its contents became public.
Cabinet Office civil servant David Keogh has been charged under the Official Secrets Act with passing it to Mr Clarke's former researcher Leo O'Connor.
He was bailed to appear at Bow Street Magistrates Court next week.
Mr Clarke refused to discuss the contents of the document which he received, saying his priority was supporting Mr O'Connor, who he said did "exactly the right thing" in bringing it to his attention.
A Downing Street spokesman said: "We have got nothing to say about this story.
"We don't comment on leaked documents."