THE flagship tourist attraction in Sevenoaks may have to close as it falls into disrepair.
Knole, which brings in 95,000 visitors a year, is falling down.
The historic building, a former residence of Henry VIII and Elizabeth I, is crumbling, roofs are leaking and staff are battling crippling insect infestations.
Now an urgent appeal for £2.7 million has been sent out to National Trust members to help save it.
The 600-year-old Knole, now owned by the National Trust and occupied by Lord Sackville, has been open to the public since the 17th century and forced to close only once before, during riots in 1884.
Knole property manager Steve Dedman said in a letter to trust members: "We are fighting a losing battle. We are at crisis point.
"Time and the elements are taking their toll and, unless we raise vital funds, we could be forced to close Knole to the public.
"Crumbling masonry, damp rooms and insect infestations are threatening the very survival of Knole and its irreplaceable collections of furniture, paintings and textiles.
"Knole today is a pale shadow of its former glory.
"The roof is critically damaged, letting in water, and my team is battling to keep the winter elements out.
"The serious structural problems we are monitoring are getting worse and the insect infestation is proving very resistant to treatment.
"Almost every day we are finding challenges to the way we care for the world's most significant collections of Jacobean and Stuart royal furniture, tapestries, paintings and silver.
"The artefacts and objects are extremely vulnerable to the damp and Knole has extremely high levels of humidity in each of its rooms.
Many of the priceless treasures are at risk of disintegrating altogether in this environment."
The National Trust has launched a three-stage, ten-year plan to save the site.
It starts in April with emergency repairs to tackle the root cause of damp, fix leaking roofs, stop movement and install an electrical submain.
This will continue until February 2014 when conservation work will move inside and contents will be removed to a conservation studio for five years.
Jane Maltby, marketing manager at Knole, said: "We want to safeguard the house, and a certain amount of money will need to come from the public.
"It is the most fragile property in the National Trust, and there are some very severe faults, but we need the support of the public and we want them to come on this long journey with us."
Visitors to Knole this week reacted with horror to the news.
David Gamble, chairman of the Sevenoaks Society, said: "We see this as a really important initiative. Where would we be without Knole? It is the foundation of Sevenoaks.
"This is the biggest project the National Trust has ever got involved with. It's very important and Sevenoaks Society will do whatever it can to support it."
He added Knole's plan to build a conservation studio would bring in overseas visitors.
"This is a tremendous opportunity for the whole community to take a part in Knole and enjoy it," he added.
Marg Wood, of Bentleys Meadow, Seal, a member of the National Trust, said: "It would be dreadful if it closed."
Gwin Jones, of St John's Road, Sevenoaks, is also a member and uses the grounds of Knole regularly. He said: "It would be a shame if it closes. It is a great boon for Sevenoaks."
Knole was shut in 1884 by Mortimer Sackville, who was fed up with visitors to the property. People in Sevenoaks rioted for their right to go in, broke down gates and threw stones at the house.
To help, go to www.nationaltrust.org.uk/knoleappeal