The government is to pump a whopping £21 billion of grants and guarantees into Railtrack it was revealed yesterday.

Announcing plans for the new body, Network Rail, Alistair Darling conceded they were "large sums by any standards" but insisted the cash was necessary.

The opposition said the taxpayer was now footing the bill for Stephen Byers' botched job.

The Railtrack Private Shareholders Group is to sue the government over the deal.