Conservatives are to seek "urgent clarification" on the rules governing questions to the Prime Minister after David Cameron was blocked by the Speaker of the House of Commons from asking Tony Blair about the Labour succession.
Opposition whips have decided not to mount a formal challenge to Speaker Michael Martin's ruling, which caused uproar at Prime Minister's Questions in the Commons.
But a senior aide to Mr Cameron said that the party was concerned that the ruling could stop him from asking questions which go to the heart of how Britain is governed.
Mr Martin intervened as Mr Cameron tried to ask Mr Blair whether he backed Gordon Brown as his successor.
Internal Labour Party appointments were "not a matter for the floor of the House", said the Speaker, adding that the weekly questions session should be used to ask the PM about "the business of the Government".
Mr Cameron's aide described the ruling as "bizarre and extraordinary" and said it would be considered by the opposition whips' office.
He later told the Press Association: "We are not going to make a formal challenge. But we will be seeking urgent clarification from the Speaker as to the types of questions we can ask.
"We feel that questions about relationships inside Government and inside the Cabinet go the the heart of how this country is governed."
MPs have not previously been stopped from asking such questions in the Commons, he added.
