The document which sparked a probe into an alleged Downing Street cover-up over cash for honours was written by Number 10 aide Ruth Turner.
No 10 aide Ruth Turner wrote the document for Jonathan Powell
It was written for Tony Blair's chief of staff Jonathan Powell, and concerned Labour's chief fundraiser Lord Levy.
An injunction barring reporting of the document's details has been amended so the BBC can say who wrote it.
In response to the BBC report, Downing Street said: "This story is inaccurate; we dispute this version of events."
But a spokesman would not specify what part or parts of the BBC report was disputed.
Attorney General Lord Goldsmith said his decision to amend the injunction did not confirm that any document had been sent or received.
Police sources have said the document was central to their decision to investigate allegations of a Downing Street cover-up.
The cash-for-honours probe began a year ago. All involved deny wrongdoing.
The amendment to the injunction on Monday was made after a request from the BBC to the attorney general.
Police are investigating allegations that honours were exchanged for loans to the Labour Party.
The probe switched its focus recently from the question of cash-for-peerages to allegations of a cover-up.
No-one has been charged with any offence in connection with the investigation.