£200,000 bill for conservation of Queen's coronation chair

• The coronation chair was built on the orders of Edward I to house the Stone of Scone. Picture: PA

The coronation chair, on which almost every monarch has been crowned since it was constructed 700 years ago, is to undergo extensive conservation work costing 200,000.

The oak artefact, which was built on the orders of Edward I, "Hammer of the Scots", to house the Stone of Scone, on which Scottish kings had traditionally been crowned, is to have what remains of its fragile medieval decorations preserved.

Only three sovereigns – Edward V, Mary I and Edward VIII, who abdicated in 1936 before his coronation was held – were not crowned on it.

But wear and tear has taken its toll since the royal seat, housed at Westminster Abbey, was commissioned by Edward I in 1300 after he captured the Stone of Scone in 1296.

Much of its rich paintings, ornate gold gilt and glasswork have been lost, and the wood was damaged by the graffiti of 18th- and 19th-century schoolboys. The Stone of Scone is now in Edinburgh Castle.

Dr Tony Trowles, head of the Abbey Collection, said: "At first sight, it looks an odd chair for a monarch to be sat in, but it originally had foliage and birds and the image of a king.

"It's a slightly battered object, but what does survive is particularly fragile and needs to be stabilised. The work is really conserving the original medieval paintwork and gilding, much of which was lost over the centuries."

The Department of Culture, Media and Sport has given Westminster Abbey a 150,000 grant towards the cost of the project, with the abbey itself contributing a further 50,000.

Conservation experts will start work at the end of this month and spend about a year examining what remains of the gold and paint.

Brown paint applied for Queen Victoria's golden jubilee in 1887 and other additions over the years, such as polish and wax, may be removed.

The imposing chair is two metres high and decorated in a gothic style reminiscent of a medieval church.

It stands on four gold lions, one at each corner, added during the Georgian era. It was decorated by Master Walter, a court painter, on the orders of Edward I. Its wide seat and back are covered with initials, names and dates carved on to its oak surface.

Much of the defacing of the chair took place when it was stored in one of the abbey's many rooms and pupils from the nearby Westminster School found what may have appeared to them as an abandoned old piece of furniture.

Dr Trowles said: "The schoolboys carved their names on it and one wrote 'P Abbott slept in this chair 5,6 July 1800'."

Marie Louise Sauerberg, a painting conservator from the Hamilton Kerr Institute, part of Cambridge University, will be working with colleagues on the coronation chair. Visitors to Westminster Abbey will be able to watch her team through a glass wall built into the side of a studio constructed within St George's Chapel.

She said: " This is such a unique and rare object – we need to have it somewhere like here where we can we really have a look.

"It's difficult to say whether there will be any great finds. We're right at the beginning of the process and people have already looked at it in the past – before the Queen's coronation in 1953 they did a very good study. We'll just be doing our bit to add to that long history of treatment and examination.

"You have to remember something happened to it at every coronation, and it's been pretty much in non-stop use since it was made."