AFTER dedicating 33 years to bring grade I listed Allerton Castle back to its heyday, an American electronics tycoon has gifted it to the nation, to ensure its preservation as a place that the public can enjoy.

While transferring the ownership of what once was among the North's finest stately homes to his North Yorkshire-based foundation, Dr Gerald Rolph has appointed his nephew, Colonel Donald Lee Rolph, as its chief custodian.

Colonel Rolph said: "This is my uncle's way of expressing his gratitude to the community which has given him so much support, a way of giving something back."

The castle, now worth an estimated £11.5m, was rebuilt in the early Victorian era on the estate near Boroughbridge which was once home to King George III's brother, Prince Frederick Augustus, Duke of York. Local legend has it inspired the nursery rhyme by sending workers up and down a 200-ft high hill to construct its Temple of Victory, now a landmark from the A1.

In the 20th century its condition deteriorated and was nicknamed Castle Dismal by the Royal Canadian Air Force, which used it as a wartime headquarters. The historic property suffered further after it was inherited in the 1960s by a 12-year-old boy, whose bequest stated he could not receive the finances needed to revamp it until he was 30.

When Dr Rolph, a former vice president of Tandy, first saw the property on a visit to Britain in 1983 when it was in a parlous state, with broken floors, condemned electrics and riddled with woodworm and rot.

However, he instantly fell in love with it. Dr Rolph said: "We drew up a contract very quickly because I was worried about that word you have – gazumping."

For decades he poured his energies and fortune into restoring the property and travelled the world gathering a exquisite gothic and Georgian antiques, until, in 2005, a blaze which was fought by 100 firefighters almost completely destroyed the stately home, with the entire roof and first floor of the building collapsing.

Despite this, Dr Rolph's resolve to restore the castle never wavered. Colonel Rolph said: "He had the vision even after the fire, which was devastating to him.

"I am amazed and proud by what he has done and coming over here and being a part of this is an honour.

"I am retiring from the military in Oregon next year and it's my goal to carry on what my uncle has done with the restoration.

"History was my favourite subject at school and we were taught the Grand Old Duke Of York nursery rhyme and had pictures of it."

Initial plans include work on several grandiose rooms, including Lady Mowbray's boudoir and numerous hallways before refacing the castle's exterior stonework. Following that Colonel Rolph will tackle the parkland, developing such features as raised beds and paths "to return its grandeur".

To help realise his ambition, the military logistics expert is planning to relaunch an educational centre at the castle for university students, who will help with the painstaking task of revealing hidden architectural gems.

To help generate funds for the work, the castle, which is a popular wedding venue, will be open to the public on Wednesday and bank holiday Monday afternoons, from Easter to October.

Colonel Rolph added: "We are also doing this for English and world heritage. This is a venue for people to use. To me, something like this needs to be out there for people and it is a fantastic way of being able to express our gratitude to the people of England."