A decision on whether Mervyn King will be reappointed governor of the Bank of England will be taken next year, a spokesman for the Prime Minister said yesterday .

A question mark has been hanging over Mr King's head since his handling of the Northern Rock crisis came into question.

Asked in August whether he would seek another five-year term as governor, Mr King said no decision would be taken immediately. Mr King's initial term will end next June. The post is approved by the Queen on advice from the Prime Minister.

Michael Ellam, a spokesman for Gordon Brown, said yesterday that he "would not expect anything to happen this year".

That was a shift in his position from earlier in the day when he said: "There will need to be a process in relation to reappointment - but the Prime Minister's view is that the governor of the Bank of England is doing a first rate job."

This only served to increase speculation about Mr King's future in the wake of the Northern Rock crisis, which led to the first run on a major British bank for 150 years, and subsequent allegations about who was to blame for failing to stop it.

There were also suggestions last night that Mr King and Chancellor Alistair Darling are to be questioned again by the Treasury select committee on alleged differences in their accounts of what happened in the lead-up to the Northern Rock crisis.

The Times newspaper's online edition said the committee had scheduled a second set of hearings, starting in December, with Mr King, Mr Darling and the head of the Financial Services Authority, Sir Callum McCarthy.

It cited Michael Fallon, a senior Conservative member of the committee, saying that a BBC interview with King this week over what happened "appears to have thrown up further discrepancies".

The Treasury and Mr King clashed over claims from the central banker that Mr Darling vetoed Lloyds TSB's prospective rescue bid for Northern Rock.

Mr King told BBC radio he advised Mr Darling that it was "a matter for government" whether to provide the £30 bn loan required for the deal to go ahead.

The Treasury called the claims "wrong", insisting the government was not approached "with a substantive proposition for Northern Rock that required state support".

A spokesman for the Select Committee said that Mr King and the FSA are likely to appear before the committee before Christmas, though no precise dates have been set yet.

Next week the committee is to question representatives from ratings agencies Moody's, Standard and Poor's and Fitch.

The agencies have been accused of not doing enough to warn investors of the risks surrounding assets linked to the troubled US sub-prime sector.

Meanwhile yesterday, shares in Northern Rock slumped 12 per cent amid reports that worried savers have withdrawn more than £10 billion from the bank.

Documents sent to would-be buyers of the stricken firm say customers have taken out £10.5 billion since the bank was forced to seek emergency funding from the Bank of England in September, it was claimed.

The sum represents nearly half the £24 billion in retail deposits held by the bank, which was unavailable for comment.

Northern Rock was the leading faller in a turbulent start for London's FTSE 100 Index, which lost 80 points in early trading before recovering.

The falls followed major losses on Wall Street overnight, as Morgan Stanley became the latest investment bank to warn of major write-downs following the sub-prime mortgage crisis in the US.

The bank's losses on mortgage-related debt could potentially reach $6 billion (£2.85 billion).