Why Blair is so keen to clear his name

The Press Complaints Commission faces one of its trickiest tests as it mulls over a complaint from Downing Street against The Spectator magazine, The Mail on Sunday and the London Evening Standard over reports that Tony Blair tried to win an enhanced role at the Queen Mother's funeral.

The Prime Minister was adamant: this was not about the rough and tumble of daily media criticism. "He is not prepared to allow people to believe the lie that his initial reaction on hearing of the Queen Mother's death was, 'How can I get on the act?'" said one aide. According to the Blair camp, a piece of erroneous gossip has been elevated into a "fact", and it is no defence to argue that the gossip was so interesting in itself that it should be reported.

No 10 claims there was no attempt to check the claim before Peter Oborne, The Spectator's political editor, went into print and then stuck to his guns in the Standard. Then The Mail on Sunday took up the story with relish.

Ministers insist this is not a "test case" designed to fire a warning shot at Fleet Street. But perhaps there is a desire to warn the most hostile papers that Mr Blair will not let them "print anything" in an attempt to damage the Government.

The dispute could have been settled amicably, and perhaps should have been. Alastair Campbell would initially have settled for a correction in The Spectator, but this was declined. Now both sides are on their high horse. In an editorial this weekend, The Mail on Sunday accused the Prime Minister of "seeking to use the PCC in a wholly new way which – if he succeeds – will allow politicians to challenge the interpretation of their actions by the media in this country". Writing in The Guardian yesterday, Mr Oborne claimed that Mr Campbell "cannot always be trusted to tell the truth".

What, then, actually happened? After the Queen Mother's death, Clare Sumner, a private secretary at Downing Street, sought to clarify the Prime Minister's role with Black Rod, Sir Michael Willcocks, the parliamentary official in charge of the lying-in-state.

Ms Sumner had found a document, written in 1994 after guidance from Buckingham Palace, saying the Queen Mother's coffin would be greeted at Westminster by the Prime Minister and Leader of the Opposition.

No, said Black Rod: the coffin would be greeted by the Speaker and the Lord Chancellor. Fine, replied Ms Sumner, according to No 10, which insists that Mr Blair was unaware of these discussions. Sir Michael has confirmed in a statement: "At no stage was I asked to change the arrangements."

No one is suggesting that Mr Oborne, a respected Westminster journalist and Mr Campbell's biographer, made it up. The most common theory at Westminster is that someone built a routine and innocent telephone call between No 10 and Black Rod into a mountain it never was.

Perhaps the "gossip" stemmed from someone in royal circles unhappy at Mr Blair's treatment of the Palace since becoming Prime Minister, including the Blairs' walk down Whitehall that upstaged the Queen on the day of the Queen's Speech. Whatever the truth, the stakes are now high, and, unless the PCC can come up with a classic fudge acceptable to both sides, someone is going to lose badly.