The house in Hampstead, London, now a museum visited each year by more than 20,000 pilgrims from as far afield as Japan and America, has damp and rot invading the public areas and the curator's office. Large external cracks run from upper to lower windows, plaster is falling off the walls in the basement kitchens, and the reproduction Regency wallpaper is damp and discoloured. Water threatens to seep through on to some of the 6,000 books.
The poet's bedroom is particularly badly affected: a lithograph had to be removed from one wall with large patches of damp and fungus growing on it. The house was completely restored in 1974-5.
Built in 1815 as a semi- detached villa, it is where Keats met and wooed Fanny Brawne; he wrote "Ode to a Nightingale" in the garden and walked with Coleridge on nearby Hampstead Heath. Manuscripts, paintings and mementoes are on display, recording the poet's brief but productive residence before ill-health took him to Italy, where he died in 1821.
Keats House appears to have become the victim of a lengthy transaction between two local authorities over its future ownership, which has left maintenance on hold.
The house was rescued from demolition in 1920 by public subscription, largely from the United States, and bequeathed in perpetuity to Hampstead Borough Council, now the London Borough of Camden. Last year Camden spent pounds 130,000 on keeping it open, out of a leisure budget in excess of pounds 20m.
Keats was born near Moorgate, in the City, and for the past year Camden has been seeking to transfer responsibility for the house to the Corporation of London, which is also responsible for Hampstead Heath.
The house's dilapidation comes at a time when interest in Keats's life and work is increasing. Keats is the only English poet to have had two nominations in the top 10 of the recent poll to find the nation's favourite poem: "Ode to Autumn" came sixth and the "Ode to a Nightingale" ninth.
On 31 October, admirers of Keats will lay a wreath at Poets' Corner in Westminster Abbey to celebrate the bicentenary of his birth in 1795. The BBC is running a series of tributes on television and radio.
The poet Andrew Motion made frequent visits to the Hampstead house to study its archives for his forthcoming biography of Keats. In the room where he worked, damp runs down behind the bookcases and paper is starting to come down from the ceiling.
"The wall is only one brick thick," he said, "and when it rains the water soaks through like blotting paper. It's one of the great icons of literary life in this country. We make a great fuss of Keats in theory, but we can't even keep his house in good repair. No other country would allow it."
A spokeswoman for Camden council said yesterday: "We are still in discussion with the Corporation of London. We have made an application to the Charity Commission for permission to transfer the trust, and we are waiting for their approval. We are aware that the house has not been given the attention it deserves."