THE Hogwarts Express steam train used in the Harry Potter films has been forced off the rails after vandals spraypinted it green and silver.

The graffiti artists were yesterday branded "mindless morons" for the thousands of pounds worth of damage they have caused.

The culprits broke into a depot in Scarborough, North Yorkshire, and vandalised two 64ft carriages of the Olton Hall train, which has featured in both Potter films.

The British Transport Police said the graffiti was "tagged" with the signature "slobs" and pictures of the work have been sent to experts in a bid to trace those responsible.

A police spokesman said: "The damage was quite extensive and will cost in the region of £3,000."

West Coast Railway bosses, the train's operators, have attacked the vandals, saying it was a pointless action that has angered a lot of people.

Spokesman James Shuttleworth said: "This is serious damage to property and should not be treated as a soft crime under any light.

"The carriages were in wonderful condition and it is going to cost a lot of money to get them back that way."

He admitted that last Saturday may not be the first time the culprits had broken into the depot - with slight graffiti damage spotted on a different carriage a fortnight earlier.

"I don't know how they have broken in but these sorts of people get in to places where castor oil wouldn't - they are just mindless morons," added Mr Shuttleworth.

The train features in the blockbuster movies to take Harry Potter and his friends from the mythical Platform 9, at London's Kings Cross Station, to Hogwarts School of Witchcraft and Wizardry.

Anyone with information about the break in and graffiti is asked to call the police on (0800) 405040.