Gordon Brown could have saved £80 million of taxpayers' money if he had renationalised Railtrack instead of converting it into Network Rail, a Liberal Democrat peer claimed yesterday.

"Gordon Brown could have cut Network Rail's huge interest bill of £415 million last year by up to £80 million by issuing gilts, the cheap and honest way to fund this vital public service," said Treasury spokesman Lord Oakeshott.

Meanwhile, announcing its results yesterday, Network Rail announced it had fallen £290 million into the red.

The results were described as "disappointing" by company chairman Ian McAllister, although there had been a 33 per cent increase in maintenance spending.