The Conservatives have seized on reports in the Mail on Sunday that a memo by parliamentary official Black Rod claims that he faced "sustained and constant pressure" from Downing Street to change the arrangements for the Queen Mother's funeral to give the prime minister a more prominent role.

Party chairman David Davis called on Tony Blair to deliver a Commons statement to explain events leading up to the funeral.

The government insists, however, that the latest claims "changes nothing". "There is no evidence at all to support the claim that there was an intention to enhance the prime minister's role," said a spokesman.

The memo by Black Rod, Sir Michael Willcocks, cites the Lord Chancellor Lord Irvine as a witness to the Press Complaints Commission.

On Friday, Number 10 published a 30-page document establishing its version of the saga, after withdrawing its complaint with the PCC.

The Times quotes a "senior courtier" as saying the Queen is unhappy that the memory of the funeral is being tarnished by the row and is concerned that a royal official is behaving in a "partisan political fashion".