Tony Blair suggested that David Blunkett could make early return to the Cabinet if Labour wins the general election.

In his first comments since Blunkett's resignation as home secretary last week, the prime minister described him as a “tremendous colleague”.

When questioned whether Blunkett could return to frontline politics, Blair said: "I have made my admiration for David very clear and it remains. He's been a tremendous colleague.

“He's done a great job for us, first as education secretary, then as home secretary. The future is something we will have to approach in the future."

Although the Tories are continuing to press for a full inquiry into the affair, Blair made it clear he felt that the resignation was sufficient.

"As far as I am concerned, we have drawn a line under that," he said.

"He was the person, first of all, who asked for this inquiry to be set up. He accepted that what he originally thought had happened had not happened.

"But I think Sir Alan Budd also accepted there wasn't some conspiracy or cover-up and I just think a line should be drawn under now and we should move on," he said.

Meanwhile, Sir Alistair Graham, chairman of the committee on standards in public life, has criticised Sir Alan Budd's report for failing to answer key questions.

Describing Sir Alan's inquiry as "unhelpfully narrow", Graham said it had failed to establish whether the former home secretary breached the ministerial code of conduct or whether officials in his private office breached its civil service equivalent to help him.

"Sir Alan Budd has clearly conducted a thorough and precise inquiry against the terms of reference he was given and has established some, although not all, of the important facts about the events that were the subject of the particular allegation against the then home secretary," he said.

Whitehall

Reports suggest that at their regular weekly meeting on Wednesday, permanent secretaries from all government departments agreed to bring in new rules to stop ministers abusing their position by giving special treatment to friends or constituents.

John Gieve, the Home Office permanent secretary, is reported to have raised the need for new guidelines.

Sir Andrew Turnbull, the Cabinet secretary, agreed to look into the question and new rules are expected early next year.

Gieve has already brought in guidelines for Home Office staff, which say: "Particular care needs to be taken over cases in which a minister may have a personal interest or connection, for example because they concern family, friends or employees."

Ministers should disclose their connection to the minister taking the decision, who should avoid "special treatment".

Quinn

It has also emerged that Kimberly Quinn kept a detailed three-year diary of her relationship with Blunkett.

However, “friends” are quoted in Thursday’s press warning her against going public, saying such a move would jeopardise her position as publisher of the Spectator.

One said: “The Spectator gives her a social status that she craves. If she kisses and tells she is a social pariah. She would be mad to do it.”

Stephen Quinn, her husband, denied she would sell her story.

"She will never publish anything about this," he said.

"It would bring humiliation on me, on Kimberly and our children. I can’t think of anything more despicable to do."