Plans to refurbish the Forth Bridge have been thrown into confusion with the scrapping of a contract mid-way through its duration.

Railtrack said only a quarter of the work had been done on the world-famous rail bridge and the agreement was being ended by mutual consent.

Rigblast, the Aberdeen-based company which had a team of up to 300 people working on the bridge, declined to comment on the implications of the move.

'National asset'

Railtrack said it remained committed to completing the project to the highest possible standard on "this important national asset", with safety the first priority.

The rail firm decided in 1997 to undertake a four-year project which would cover the structure in a glass-based substance designed to protect the bridge for 25 years.

It was thought this would be better than the traditional paint, which had to be applied continuously.

But Rigblast ran into problems with the contract and last autumn a joint review was set up.

Sandy Clark, managing director of Rigblast, said at the time: "We have been severely impacted by weather on the job.

Weather 'factored in'

"A certain amount of bad weather provision was factored into the contract, but the actual bad weather has been four times what was expected."

Work on the structure, which was opened in 1890, was due to be completed by the end of 2001. The new date is unclear.

Wilkie Hook, one of the sub-contractors on the job, went into receivership early in February, blaming the contract dispute between Railtrack and Rigblast.