Work on the £9.8 billion modernisation of the West Coast Main Line could be deferred by up to a year to save money, the Rail Regulator Tom Winsor said today.
He produced a report he had commissioned showing Network Rail's "poor organisation" on the West Coast project.
Mr Winsor also called on NR - Railtrack's successor company - to slash billions of pounds from its costs before he announces in December just how much the company can charge rail operators for using the network.
Already dogged by delays and cost overruns, the West Coast project is designed to reduce journey times between London, the Midlands, the north of England and Scotland.
Speaking on BBC Radio 4's Today programme, Tom Winsor said the savings could be made "at the cost of deferring work that does not need to be done now".
He went on: "I am consulting on a number of options, one of which is to do some parts of the (West Coast) upgrade later than are presently projected, so as to save perhaps as much as £1 billion.
"The West Coast Main Line is going to achieve 125mph operation on most of its lengths by September 2004.
"That's Manchester to London and Birmingham to London. But it may be that other parts of the network will have the increase in line speed, in the capability of the network, deferred a little bit in order to save a lot."
Asked how long that delay would be, he said "perhaps a year". Other work would also be deferred "and may not be done", he added.
Mr Winsor went on: "It is not always necessary to replace assets now when they are still in good condition and, with proper and timely maintenance, could be kept going for longer and still be performing properly."
He said taxpayers wanted to have an efficient and safe railway "at a proper price and value for money".
Mr Winsor said the new management were "getting a grip" on the situation they inherited from Railtrack, adding: "I am right behind them in terms of the work they are doing but I believe that they can move these improvements faster than they are projecting."
He said costs in the wake of Railtrack's "extraordinary overreaction" to the Hatfield crash had "exploded".
He added: "The decision I must make is all about getting out of the system unnecessary cost and inefficiency."Reuse content