Vince Cable has accused Gordon Brown of being "petrified by indecision" on the future of Northern Rock.

Speaking during prime minister's questions in the Commons on Wednesday, the acting Liberal Democrat leader called on the prime minister to ensure that the estimated £25bn loan to the troubled bank would be repaid in full.

Cable told MPs that Bank of England lending to Northern Rock was increasing by £3bn every week, and he accused Brown of being "dogmatically opposed" to the "common sense solution" of temporary public ownership.

"There is a sensible way of rescuing this bank," Cable said.

"Why is [the prime minister] so dogmatically opposed to the common sense solution of public ownership on a temporary basis, which will protect the public loan.

"Is it that he regards the advocates of this policy - which now include the FT, the Economist and apparently his own civil servants - are they all too left wing? Or is he petrified by indecision?"

Brown said the company must be rescued to ensure economic stability and protect mortgage holders and shareholders.

He told MPs that "all options are on the table but we are trying to find a private buyer", insisting the government had "taken the action that is necessary".

"I believe at one stage there was all-party support for that," the prime minister added.

"I believe we've done the right thing and I believe any settlement of this with any potential buyer will insist that the public funds are properly protected."