But, although weary British commuters might envy the space and facilities enjoyed by the Queen, the "Formica laminated" surroundings are some way from a royal Orient Express of popular imagination.

In fact, efforts to dispel that image prompted Buckingham Palace to grant unprecedented access to the interior of the train before the Queen made use of it for her recent Golden Jubilee tour of Britain.

I don't think it's that grand or that comfortable

Edward Leigh MP

But that has not stopped the House of Commons public accounts committee raising questions about the cost of the train - which is seldom used - particularly in comparison to the alternatives.

If it is scrapped it is thought likely the Queen would lament the loss of her loco, after already giving up the Royal Yacht Britannia five years ago.

Train 'not grand'

Edward Leigh, the Conservative chairman of the committee, said the royal train was twice as expensive as using air travel but hardly luxurious.

"I think people imagine the royal train is a rather grand affair but it's not really," he told BBC Radio 4's Today Programme.

"It was built in the 1960s or '70s, it's a rather Formica laminated affair.

The Royal Train has not been refurbished in years

"I don't think it's that grand or that comfortable."

The train is usually housed in a rail works shed near Wolverton station in Buckinghamshire and enjoys occasional outings - the most recent being for the Jubilee tour.

It has seen some unexpected action. In June 2000 a royal bodyguard accidentally fired two shots from his gun on the train while the Queen and Duke of Edinburgh were on board.

Fortunately no one was injured - the royal couple were asleep elsewhere - but a table and part of the carpet were damaged.

The train is also said to be a favoured means of overnight travel for the Royal Family and the comfort it provides to the Queen, given her age, is also recognised.

The first royal train went on the rails in 1842 to take Queen Victoria from Slough to Paddington, but the current model has been in existence since 1977.

Converted carriages

Since that year, the annual cost of the Railtrack-owned train has been reduced from �1.9m a year to �600,000 a year, even though it was only used 17 times last year - a cost of �35,000 per journey.

The age of the carriages on the royal train vary, but the Queen's and Duke of Edinburgh's saloons were built in 1972 and converted for royal use for the 1977 Silver Jubilee.

The train is fully fitted out with modern office and communication equipment

Pulled by a standard locomotive - currently a choice of two named the Prince William and the Prince Henry - it is painted in royal claret.

The train's carriages boast bedrooms, bathrooms and sitting rooms and are fully fitted out with modern office and communication equipment.

The Prince of Wales' lounge car contains easy chairs, a writing desk, a 1960s-style Roberts portable radio and pictures from his private collection.

Plastic flag

A carriage for senior members of the Queen's staff has single bunk beds with bedside tables and a breakfast table.

The Queen's own salon is 75ft long, air-conditioned and electrically heated.

It contains a sitting room, bedroom and bathroom for the Queen, as well as accommodation facilities for her dresser.

En-suite bathrooms have pink plastic baths and sinks with Pears soap in dishes, plain mahogany toilet seats and clear plastic shower curtains.

A compartment used as an office by various private secretaries has a fax machine and telephone bearing the Queen and Duke of Edinburgh's extension numbers.

A bullet hole from an accident in June 2000 has yet to be repaired

Items on show when the carriages were opened up to the media earlier in the year included two battered red despatch boxes used for the Queen's correspondence and a plastic Union flag.

A 2002 copy of Who's Who was also at hand.

And the Buckingham Palace staff dining car is laid out in the style of a first-class train carriage.

The train is operated jointly by the English, Welsh and Scottish Railway Company.

Drivers are said to be drawn from an elite pool working in the railway industry.