The Chancellor struggles as all is revealed about Northern Rock

A detailed analysis of the lending fiasco by the country's top banker put a fresh strain on relations between the Bank, the Treasury and Downing Street.

Mervyn King raised a series of difficult questions about the events leading to the Government's pledge to protect the savings of Northern Rock customers.

Gordon Brown was also drawn into the row as Mr King said he lobbied him for new legislation to avert a banking crisis, with no success.

The implication is that the Prime Minister ignored advice that could have avoided the debacle.

The Governor's intervention caused consternation at Westminster and prompted Tory claims that Mr Darling was losing his authority.

Mr King is known to have been stung by City criticisms of his role in the saga, amid growing doubts about the health of the banking sector in the wake of the American sub-prime mortgage meltdown.

Mr King revealed in a BBC interview that in the days before the Government stepped in to guarantee Northern Rock deposits, Mr Darling had rejected a proposal from Lloyds TSB to take over the ailing bank in exchange for a £30billion loan at commercial rates from the Bank of England.

He said he told the Chancellor: "This is not something which a central bank can do. They don't normally finance takeovers by one company for another, let along to the tune of £30billion, which is rather a large amount of money."

Northern Rock's need for emergency cash sparked the first run on a UK bank for almost 150 years. Thousands of account holders queued outside High Street branches for days to take out their money.

Bank sources insisted last night that he had not meant to challenge Mr Darling, but his comments piled more pressure on the Chancellor.

In a statement Mr King said: "There was and is no disagreement at all between the Chancellor and me on this issue."

But barely four months into the job, Mr Darling is facing mounting questions about his ability to withstand pressure from his predecessor at the Treasury.

Mr Brown forced the Treasury to bring forward last month's Pre-Budget Report as part of his abandoned plans for an early election, prompting fears that economic policy was being dictated by Number 10.

Suspicions that the Prime Minister is keeping a tight grip on his former department were reinforced last week when Mr Brown leaked Treasury plans for a compromise on reforms to Capital Gains Tax.

Mr Darling, who has been candid with the Premier in private about the need to end public interference, has also been hit by Tory claims that Mr Brown's close advisers are meddling in Treasury decision-making.

The Tories claim that Shriti Vadera and Ed Balls, who worked for the Prime Minister when he was at the Treasury and who are both now ministers, are still involved in shaping economic policy, a claim Mr Darling denies.

Friends say he has warned the "young turks" led by Mr Balls, who last month talked up the prospect of a November election only to be vetoed by Mr Brown, that their ambitions are putting Labour's hopes of a fourth election victory at risk.

Shadow chancellor George Osborne said: "Alistair Darling is struggling to prove he's up to the job of Chancellor at the very moment when we need strong leadership at the Treasury.

"Gordon Brown is trying to control everything and as a result he can't run anything."

Mr King told the BBC it could be months before the full extent of losses in the fallout from the Northern Rock crisis are revealed. But he said he was optimistic the British banking system had "come through".

A Treasury spokesman said: "As the Chancellor made clear to the Treasury Select Committee on October 25, at no stage was the Government approached with a substantive proposition for Northern Rock that required state support.

"Instead there was a general inquiry as to whether the Bank of England might provide commercial banking facilities of up to £30billion at non-penalty rates for up to two years, in the same way as an investment bank.

"In any event this general inquiry was not followed up with any detailed proposal."