The government has pumped £25 billion or so into Northern Rock. I believe the only way to safeguard the public's money is to nationalise Northern Rock, ideally with the major shareholders getting no compensation, this will safeguard people's money and jobs and ensure £25 billion of public money isn't just used to prop up failing private business.
I see Richard Branson and friends are circling like vultures, US companies are expected to make bids too. I think however nationalisation is the only way forward; I don't see any of the potential buyers wanting to stand behind Northern Rock without the government and Bank of England's support (and money).