Forty firefighters from three brigades tackled a fire which broke out in an outbuilding at Dobroyd Castle, Todmorden, on Sunday.
The historic listed building is used by the Robinwood Activity Centre Ltd and offers a range of sports and activities.
Todmorden Fire Station watch commander Jim Priestley said: “We got the call at 6.18am and within a minute of arriving the crew asked for another five pumps which arrived from West Yorkshire, Greater Manchester and Lancashire fire services.
“The fire was in a single-storey, 30m by 15m room used to house The Dungeon and The Piranha Pool which will have to be demolished.
“Around half of it was on fire and crews managed to stop it spreading to some adjoining two-storey buildings.
“They used two mainline jets and drew water from a nearby pond. The fire was under control by 9am. They did a really great job and managed to bring it under control very quickly. Their actions saved a considerable amount of damage happening to adjoining property.
“The cause of the fire is still under investigation but there’s no reason to suppose it was suspicious and was possibly the result of an electrical fault.”
The castle itself was built between 1866 and 1869 after a rich industrialist, John Fielden (Jnr) fell in love with a local woman, Ruth Stansfield and asked her to be his wife.
She is supposed to have replied was that she would marry him if he built her a castle which he duly did. Since the family sold it the property has had a variety of uses.
The Home Office used it between 1942 and 1979 as a place for teenage boys to learn manual skills such as building or carpentry alongside the rest of their curriculum.
Later on it was run as the privately run Castle School for 20 boys with emotional and behavioural problems who were educated there.
Following its closure in 1989 the castle lay unused for six years.
Then in a bizarre twist it was bought for £320,000 by Buddhists of the New Kadampa Tradition in 1995, whereupon the building became the Losang Dragpa Centre.
More recently Robinwood Activity Centre Ltd. acquired the castle and grounds for £2.2 million in 2008 and by March 2009 had transformed the Castle into a popular activity centre.
