The House of Commons Public Accounts chairman has called the government's handling of the West Coast franchise a "fiasco."
Margaret Hodge, Labour MP for Barking, said: "The DfT's handling of the West Coast franchise was a first-class fiasco."
"It has left the Government's entire policy on rail franchising in disarray, as a further three competitions have had to be put on hold.
"The total cost to the taxpayer of putting it right is currently unknown but is likely to be significant."
Ms Hodge said the Dft had "blundered into this major and complex competition for one of the biggest franchises in the country without even knowing how key parts of its policy were to be implemented".