By Paul Lewis
BBC Radio 4's Money Box
Northern Rock shareholders should be protected against further losses by the government.
That plea was made to the BBC by the UK Shareholders' Association which called on the Treasury to support the bank.
It said that would stabilise the business and give it a long-term future.
But BBC business editor, Robert Peston, said Northern Rock could not survive as an independent bank.
He told BBC Radio 4's Money Box programme: "It seems that probably Northern Rock's days of independence are well and truly over.
"Investment banks have been appointed by the company and the Treasury to examine a sale."
But he said each side had different objectives.
"The Treasury and chancellor - even the prime minister - would like this resolved as soon as possible and Northern Rock put into safe hands.
"But Northern Rock believes it is a viable business, and it ought to be able to conduct disposal in an orderly way, that maximises shareholder value."
Roger Lawson, a director of the UK Shareholders' Association, fears that the government will rush Northern Rock into a sale that could destroy any remaining value it has.
"We do not want the government or the Bank of England pushing the company into a fire sale.
"We would like the government to provide reasonable support to the company so it stabilises its business and has a long-term future."
His concern is that shareholders could lose what little remained of the value of their shares.
When Northern Rock converted from a building society in October 1997, every member was given 500 shares worth £4.51 each - a windfall of £2255.
The share price peaked at £12.51 in February 2007, valuing this windfall at £6225.
But at the end of September, the price was just £1.79 - so 500 shares were worth just £895.
At its worst shareholders could get nothing.
And Robert Peston says it will be some time before it is clear what shareholders may get.
"The big question to decide over the next few months is - what value is there in the brand name and Northern Rock as a business?
"Remember, even before the emergency lending was made, and the run on the bank, Lloyds TSB estimated the value of shares at about £2.
"There has been a lot of damage done since, so it is not at all clear that in a sale the shares would be worth even £2.
"It has had a tremendous blow to its reputation and it will take two or three weeks more, before we can see what future this bank has."
BBC Radio 4's Money Box was broadcast on Saturday, 29 September 2007 at 1204 GMT.