Plans to hire out the royal train to mere commoners in an attempt to drive down costs have been stuck in the sidings for more than a year.
The Royal Family, which has used the luxury train 25 times in the past 12 months, undertook last April to reduce its £1.15m-a-year cost by inviting government departments and charities to apply to book the train on occasions deemed to be in the national interest.
However, the offer has been taken up only once, by the Foreign Office. For most of the the time the eight carriages stand in a Buckinghamshire siding.
The cost of hiring the train is about £17,000 for a day and £25,000 overnight but, although there have been preliminary inquiries from several organisations about making use of it, none has yet put forward firm proposals. MPs are now urging a rethink.
"The royal train is a luxury the nation can no longer afford," claimed the Labour MP Gordon Prentice. "In this day and age, the idea that an expensive train should be left in a siding for most of the year is absurd."
Mr Prentice is not alone among his colleagues in believing that the train should be more aggressively marketed if it is to remain of service to the nation, and that otherwise it should be scrapped.
"This is a modernising government. That is what the Prime Minister always tells us, and here we have this asset which could be marketed more effectively than it clearly has been," Mr Prentice added.
"This needs to be looked at. There must not be a no-go area when it comes to royal transport."
In the 12 months to 31 March this year, the royal train was used eight times by the Queen, 14 times by the Prince ofWales, twice by the Duke of Edinburgh and once by the Princess Royal. Its most notorious use was in 1997 when it was used to take the Queen from Victoria station in London to the Derby - a 20-mile run which cost £11,800.
The train consists of carriages drawn from a total of eight purpose-built saloons pulled by one of the two royal diesel locomotives, Prince William and Prince Henry. Each carriage is decked out in maroon with red and black coach lining and a grey roof.
Available carriages include the royal compartments, sleeping and dining cars. The Queen's Saloon has a bedroom, bathroom and sitting-room with an entrance which opens onto the platform.
The Duke of Edinburgh has his own area with a similar layout and a kitchen. Both saloons are decorated with Scottish landscapes by Roy Penny and Victorian prints of journeys.
Buckingham Palace insists that the train is "not really suitable for large-scale entertaining" and anyone wishing to use it would have to meet strict criteria.
A spokesman for the palace said: "The train is not available for general commercial hire because of national prestige reasons, in the same way that the royal yacht wasn't hired out when it was commissioned in the Royal Navy."
But the lack of take-up among eligible groups under the 1999 scheme overseen by the Deputy Prime Minister, John Prescott, has led to renewed calls for the train to be sent to the scrapyard.
Another Labour MP, Alan Williams, said: "For years I have argued that the royal yacht and the royal train were extravagant luxuries. Now the palace has been given its own budget for transport they are demonstrating how much the taxpayer previously, unnecessarily, paid for both the yacht and the train."
Mr Prentice suggested that if the train could not be more widely used it should be scrapped in favour of the Royal Family using a special carriage attached to ordinary passenger trains.