The attorney general has again insisted he will not stand aside from any decision to prosecute allies of the prime minister over cash-for-honours claims.

Lord Goldsmith said on Sunday he had to have a role, should charges be laid, as he is accountable in Parliament for the actions of the Crown Prosecution Service (CPS).

The comments came after police investigating the allegations on Friday submitted a file to the CPS.

Prosecutors will now decide if there is enough evidence to justify charges against figures including Tony Blair's chief fundraiser Lord Levy, head of government relations Ruth Turner, chief of staff Jonathan Powell and Labour donor Sir Christopher Evans.

All concerned have strongly denied any suggestion of wrong-doing and the CPS may decide to drop the case without consulting Lord Goldsmith, as it did against a previous suspect, former headteacher Des Smith.

However critics have urged the law officer to stand aside over fears of an apparent conflict of interest because he is also a government minister, as well as a former Labour donor.

Director of public prosecutions Ken Macdonald has already said he will stand aside from the CPS decision because of his close personal ties to Blair and his wife Cherie.

But the attorney general told Sky News: "The director of public prosecutions has made it clear he has stood aside and that means there is no other senior person who can express a view in relation to this.

"There are some offences which actually by law require my consent.

"But over and above that, I am responsible by statute for the superintendence of the CPS and accountable to Parliament for the decisions it takes and I am the only person who is accountable to Parliament for the decisions it takes and I don't think I can stand aside."

He said it was "normal" for his office to be consulted in "sensitive and complex cases" and outlined plans for extra scrutiny and accountability over the decision.

"I can assure you and everyone else that, if I am consulted, any decision will be taken objectively, on the evidence, independently of government, because my first duty is to the law, not to party politics.

"My office will appoint independent counsel. I will consult the opposition parties on the identity of that person and make public the advice that is given if there is not a prosecution."

However the peer refused to commit himself to accepting the judgment of the independent counsel on the CPS recommendations.

"It is highly likely that I will, but I don't think I can just rubber-stamp the decision in advance," he said. "He might take a different view from the CPS, for example."

Lord Goldsmith was also critical of apparent leaks from the inquiry or prosecution team to the press, which he said were "not helpful".

The minister suggested that an investigation may be launched into the handling of the inquiry, saying it was "worth looking" at who has briefed the media.
 
"I think that once this is all over, one way or another it would be worth looking at just what has taken place in terms not, I think, of a formal inquiry," he said.

"I think it would be worth understanding what has taken place, because a lot of people have expressed concern, both from the point of view of those involved as potential defendants and from the point of view of the general public."