The reconstituted Northern Rock board seems to like it. Chairman Bryan Sanderson calls it "very good news". Our battered UK government seems to like it. Downing Street sources claim it meets the Chancellor's pre-requisites of protecting taxpayers and depositors, while contributing to wider financial stability.

But how can anyone else - least of all existing shareholders in the ailing mortgage bank, who will, short of administration or nationalisation, eventually be asked to say yea or nay - judge whether the Virgin consortium's plans for Northern Rock are worthy of the pole position that bidder now enjoys in determining the Newcastle-based group's fate?

In more normal times, Virgin and its associates would have been granted preferred bidder status.

But these are far from normal times. Full details of what is proposed remain, as Virgin itself said two Fridays ago, "confidential".

We know a bit more than we did then. But all that really happened yesterday is that the Rock board made public its wish "to take forward discussions on an accelerated basis" with the Virgin consortium.

Sir Richard Branson himself went further. In an open letter to Rock customers he said: "Although there is still work to be done and regulatory approval to be received before we can complete the final transaction, with the support of Northern Rock we are working hard with the government and the Bank of England to deliver our plans for strengthening Northern Rock."

Had this been a normal takeover battle, these sentiments might have seen him hauled before the regulatory authorities.

But in the battle to stop Northern Rock's travails poll uting government and the international standing of the UK's financial sector, Branson's talk of a "fresh start" and "change as a force for good" is precisely the kind of marketing chutzpah fretting politicians and bureaucrats will grab with both hands.

We do know Virgin's "indicative proposal" suggests the Bank of England will get £11bn of its £24bn or so of emergency lending back as soon as the deal goes through.

All interest accruing on the outstanding loan will be paid in cash. But as far as the other £13bn is concerned, the only stated promise is the Bank will have "a clear path towards repayment in full".

Existing shareholders certainly don't know how diluted their holdings will become, if the Virgin bid crystallises. They will be entitled to subscribe for new shares at 25p apiece. But even if they take up their entitlement in full, the Virgin consortium, thanks to a cash injection of £1.3bn and the existing Virgin Money business, will still emerge with 55% of the enlarged business.

Some existing shareholders, notably those arbitrageurs who built up significant stakes as the Rock crisis escalated, may find that bargain too hard to swallow.

Hedge fund RAB Capital, Northern's largest declared shareholder, has already called the Virgin proposals "cheeky". And small shareholders are warning the Rock's board against any "fire sale".

Another uncertainty is the significance of the various players in the Virgin-led grouping. AIG, the vast American insurance behemoth, was missing from yesterday's update, having figured in the first outline of its proposal Virgin published on October 12.

And nothing has yet been said about how big a part the others - US investor in distressed companies, Wilbur Ross; London-based hedge fund, Toscafund, chaired by former Royal bank chairman Sir George Mathewson; and the Hong Kong-based First Eastern Investment Group - will play in any deal.

Mathewson is to act as senior adviser should the venture proceed. And there's further Scottish flavour. Quayle Munro is an adviser to Virgin Management. And RBS is said to be lined up as a major funder of a reshaped Northern Rock.

The woman who ran Royal's Virgin One mortgage business until earlier this year, Jayne-Anne Gadhia, is slated as its new CEO.

Gadhia launched Virgin One back in 1998, stayed with the Royal when it bought full control of the business in 2000, and only left to run Norwich-based Virgin Money this March.

If what is, in effect, a nimble David taking over a stricken Goliath, she gets her chance to lead a hugely expanded Virgin Money, it will be a massively bigger challenge than anything she's faced before.

In the consortium's proposal, Virgin Money is valued at £250m. It has funds under management of around £2.5bn and pre-tax profits last year of just £10.2m. If the combined group materialises and ever starts making new payments into the Northern Rock Foundation it will, under these proposals, have to make annual profits of at least £638m again ( the combined profit of Rock and Virgin Money in 2006).

But there's a long way to go yet. There are rival bidders demanding to know why their proposals were left in the slow lane. There are Rock shareholders wondering if they are being hung out to dry. And there are politicians, on all sides, wondering just what chance there is of that other £13bn of taxpayers money ever being paid back to the Bank of England.

Richard Branson may need more than chutzpah to pull this one off.