LONDON - Architects who restored Windsor Castle after a fire devastated the oldest inhabited castle in the world have a message for France: Notre-Dame Cathedral will reign magnificent again over Paris, possibly sooner than grieving Parisians expect.

Notre-Dame, a symbol of Christian splendour that has captured the dreams of poets, princes and lovers through eight centuries of French history, was engulfed by flames which destroyed its roof and spire.

If there is a lesson from the 1992 fire at the home of Britain's Queen Elizabeth II, it is that one the jewels of Gothic cathedral architecture can be saved.

"We shall see Notre-Dame magnificent again," said Francis Maude, an architect at Donald Insall Associates which led the restoration of Windsor Castle and is now working on restoring the parliamentary Palace of Westminster in London.

"The French can be reassured that it can certainly be done," he said. "We would be more than ready to help."

Maude cited the reconstruction of Warsaw after World War Two, Dresden's Frauenkirche (Church of Our Lady) after the reunification of Germany, and Windsor after the 1992 fire as illustrations of what could be done.

Windsor Castle, founded by William the Conqueror in the 11th Century, survived centuries of England's often bloody history and passed through World War Two unscathed. But a fire broke out in Queen Victoria's private chapel on Nov. 20, 1992.

A spotlight might have set a curtain alight. Luckily, many areas had already been emptied of treasures to allow electrical wiring. Paintings by Van Dyck, Rubens and Gainsborough, Sèvres porcelain and ancient books were rushed to safety.

Only two works of art were lost - a rosewood sideboard and a very large painting by Sir William Beechey that couldn't be taken down in time, according to the Royal Collection Trust.

THE JEWEL OF PARIS

But the sight of flames leaping above the turrets shocked both the British public and the royal family. Queen Elizabeth cast the year, which included the separation of her son Prince Charles and his wife Diana as an "annus horribilis".

Elizabeth said on Tuesday she was shocked by the fire at Notre-Dame. Charles wrote to French President Emmanuel Macron.

"Cher Monsieur le Président, our hearts go out to you and the people of France more than you can ever know, especially in view of our experience with the devastating fire at Windsor Castle twenty-seven years ago," the prince wrote.

Repairs to Windsor began immediately after the fire and work was completed by Nov. 20, 1997, the golden wedding anniversary of Elizabeth and her husband Prince Philip. It cost around 37 million pounds ($48 million).

"It was surprising how quickly we managed to do it in the end," said Giles Downes, the architect behind some of the major restoration work at Windsor Castle.

"It always helps if you have very clear decisions taken right out at the beginning as to what your aims are," said Downes. "Once you've got those clear decisions taken, then it's a question have you got the skilled craftsmen to do the work."

At Windsor, the rubble was sifted to see which of the bits of masonry, ceiling timber, plaster or glass could be salvaged and incorporated into the restored building.

"In the initial stage, the most difficult question is how much of the standing structure can be consolidated and retained and how much of it might need to be taken down and rebuilt," said Maude.

Downes said France would have an easier time than Britain finding the skilled craftsmen for the job, because it could draw on the Compagnons du Tour, made up of thousands of highly skilled craftsmen in traditional construction.

Materials would also be available, said Downes, who is chairman of governors at Stratford's Building Crafts College.

"The roof I'm assuming is oak and there's plenty of oak available, including sessile oak which is long, straight-stemmed oak trees that they will need for these sort of projects," he said. "In northern Europe we plant more oak than we use."

Downes said the iconic stained glass rose appeared to have survived, a stroke of luck amid the ruin given the difficulty of reproducing such ancient glass.

For now, though, the burning of Notre-Dame is the cause of sorrow.

"It is a giant loss - Notre-Dame is one of the jewels of Western architecture," said Maude. ($1 = 0.7647 pounds)

(Reporting by Guy Faulconbridge Editing by Peter Graff) ((guy.faulconbridge@thomsonreuters.com; 07825218698;))