One hundred and fifty railway carriages used on services between Oxenholme and London could be scrapped despite being ranked as among the best rolling stock ever built in Britain.

A total of 299 Mark 3' air-conditioned carriages are gradually being displaced from the West Coast Main Line by the introduction of Virgin's 125mph Pendolino' tilting trains.

But Derby-based leasing company Porterbrook, which now owns the former British Rail rolling stock, has only been able to place half the older trains with other operating companies.

Some of the 25-year-old coaches have already been moved to lines in Scotland and East Anglia but others, worth around £100 million, may moulder away in storage until there is no choice but to scrap them.

In storage, mildew enters the train's air-conditioning system and wheel bearings degrade.

Cumbrian MEP Chris Davies said: "These carriages were built with public money and still have many years of useful life left in them."

Mr Davies, the Liberal Democrat spokesman on transport and the environment in the European Parliament, added: "If ever there was a case for central planning and use of resources on the railways then this is it."

He called on the Government's transport secretary Alastair Darling to take steps in his forthcoming rail review to address the issue.

Rupert Brennan-Brown, head of communications at Porterbrook, said: "These are possibly the safest and most reliable pieces of rolling stock in the network.

"Once they are gone, there won't be any more trains like them."