The campaign to keep the artist’s Dungeness chalet for the nation has just weeks to reach its £3.5m target

With just two weeks to go until its fate is decided, leading artists have waded into the campaign to save for the nation a fisherman’s shack on a bleak strip of coastline a stone’s throw from a nuclear power station.

Prospect Cottage in Dungeness, Kent, was the home of the filmmaker, artist and writer Derek Jarman, and has become a place of pilgrimage for those drawn to its stark beauty and enchanting shingle garden.

But the cottage will be sold to a private buyer unless £3.5m can be found by 31 March. It is being sold after the death in 2018 of Keith Collins, Jarman’s partner, to whom he left the cottage. A crowdfunding campaign launched in January and spearheaded by the charity Art Fund, has raised more than £2,750,000. At the launch of the fund, actress Tilda Swinton, Jarman’s close friend and collaborator, said: “First and foremost, the cottage was always a living thing, a practical toolbox for his work.”

Last week, costume designer Sandy Powell auctioned the cream suit she wore to the Oscars, which has been signed by 300 Hollywood stars, for £16,000. But with £750,000 still to find, there are concerns the target may be missed, a scenario that has dismayed Jarman’s many fans.

Facebook Twitter Pinterest Tilda Swinton, a close friend of Jarman helped launch the £3.5m crowdfunding campaign in January. Photograph: Stuart C Wilson/Getty Images

“To me, Prospect Cottage was another manifestation of his visionary, Blakean self,” said the actor Simon Callow. “In its sparseness and formality, he was showing us the world in a grain of sand, holding infinity in the palm of his hand. It’s the sort of creation that a 17th-century radical, a leveller or a digger, a ranter or a muggletonian might have made – a vision of a better world, which was always on Derek’s mind, even as the molten lava of his rage at the fuck-up of a world made by other people erupted. I guess Prospect was his sanity, his lodestone in a frequently appalling world.”

The author Philip Hoare, who is curator of Queer Nature, a forthcoming exhibition of Jarman’s Prospect Cottage work at the John Hansard Gallery in Southampton, said the cottage could be considered Jarman’s greatest work and described it as a “tarry wonder-miracle”.

“It looks like an overgrown garden shed, till you step inside and realise what a queer Tardis it is – a little bit of the Renaissance dropped into the Dungeness desert, as dark as the backrooms of Heaven, glittering like one of his film sets,” he said.

Jarman, who died of an Aids-related illness in 1994, drew strength from his garden: his diary was published as Modern Nature in 1991.

“I first read Modern Nature when I was a teenager and was bewitched by his account of making a garden in the face of his own oncoming death,” said novelist Olivia Laing . “We never think of Jarman as a nature writer, but to my mind he’s the best, not least because he understands nature is inseparable from politics and that it includes sex. He’s funny and erudite, knowledgeable about old roses and medieval history, but also bursting with gossip and capable of conveying instances of sublime, dreamlike beauty.“

“One of the things I find most inspiring about him is that he refuses boundaries. He didn’t want to be confined by any single discipline, leaping between styles and subjects in a way that feels radical even now. I wish he was still here, but his house and garden remain, an emblem of his life, a site of experiment and openness and restless creativity. As a writer I feel very strongly that we need Derek’s energy in the world right now. Prospect Cottage must be saved.”

The novelist Alan Hollinghurst, who went to the same school, Canford, as Jarman, who was 10 years older than him, recalled “this glamorous old boy who hated the school” and described Prospect Cottage as having an aura. “It’s long had a shrine-like atmosphere, in a strange quasi-religious way. Jarman was perpetually indulgent.It has a much bigger meaning than merely itself – a sort of countercultural shrine. It would be a terrible loss.”

The £3.5m would preserve and secure the upkeep of the cottage and garden. In addition, Jarman’s cottage archive, including his sketchbooks and garden plans, would be made available to the public. A residency programme for artists, writers, gardeners, filmmakers and academics would also be established. “More than 5,000 people have so far generously donated,” said Stephen Deuchar, director of Art Fund. “We need one last big push, and earnestly welcome donations both large and small.”