A furious row engulfed Michael Martin, the Speaker of the Commons, yesterday after he tried to block David Cameron from asking Tony Blair whether he endorsed Gordon Brown as his successor.
Last night, the Tory leader was seeking a meeting between the Tory Chief Whip, Patrick McLoughlin, and the Speaker to clarify his ruling, which caused uproar in the chamber during Prime Minister's questions.
The controversy threatened to undermine the Speaker's authority among Opposition MPs, who have regarded him as too pro-Labour. It came as Mr Cameron attempted to reopen wounds he exposed three weeks ago when Mr Blair was lost for words after being asked by the Tory leader whether he endorsed Mr Brown as his successor.
However, when the Tory leader renewed his attempt to embarrass Mr Blair, the Speaker stepped in. There were gasps of surprise and some Tory MPs went red in the face with rage.
The Tories were furious with the Speaker because, they said later, he appeared to be protecting Mr Blair from further embarrassment. Mr Martin, 61, a Glaswegian former metal worker - the first Roman Catholic to take the chair in 700 years -- has been dogged by controversy since he replaced Betty Boothroyd in 2001. His friends say he has been the target for snobbery at Westminster.
But yesterday his authority was on the line after Mr Martin intervened, telling Mr Cameron: "The Prime Minister is here to talk about the business of the Government... As to who is going to be the next leader of the Labour Party is for the Labour Party."
Mr Cameron, taken aback, said: "Are you honestly saying we cannot ask the Prime Minister?"
Faced with angry Tory MPs yelling at him, the Speaker threatened to suspend the sitting but allowed Mr Cameron to reword his question. Mr Blair hit back with a carefully prepared answer, praising Mr Brown and contrasting his record with Mr Cameron's past role as an adviser to Norman Lamont, the Tory Chancellor, on Black Wednesday, when he was forced into a humiliating retreat from the European Exchange Rate Mechanism (ERM).
Later, one senior aide to Mr Cameron was shaking with rage as he said: "It was utterly crass. The Speaker appeared to show a red card, then changed his mind. If he was a football referee, he would be retired immediately."
A Tory leadership source said: "It was bizarre. We are seeking a meeting with him to get clarification to see if he is seriously saying we cannot ask questions about the person who is going to be the next Prime Minister."
The Prime Minister's spokesman denied there was any pressure put on the Speaker to protect Mr Blair.
However, Mr Blair remained under pressure to clarify his own position over Mr Brown's succession.
Allies of Mr Brown last night hailed Mr Blair's remarks as his first endorsement of Mr Brown as the next Prime Minister. "At last Blair has got off the fence and endorsed Gordon," said one of Mr Brown's closest friends.
But Blairites insisted last night that the Prime Minister had not endorsed Mr Brown. "That was not his intention and he won't do that until the time is right," said one ministerial ally of the Prime Minister. "Tony has got see through the reviews of policy next spring. Then we will see."