When Ronald Grant was ten he fell in love with films, helping out the projectionist at a village hall in rural Scotland.

Like Tito, the Sicilian boy who becomes a famous director in Cinema Paradiso, the experience inspired him to devote his life to the cinema.

He spent 60 years creating a museum of cinema memorabilia crammed with everything from 1940s usherettes’ torches and handpainted film posters to the Art Deco double doors that once adorned the Kingsway cinema in Aberdeen.

Now this vast and extraordinary public resource is about to disappear from view unless a new home can be found for it in the next three weeks.

Six months ago the NHS Trust that owns the South London building where the Ronald Grant Archive and Cinema Museum is housed gave it notice to quit at the end of March. Mr Grant has been unable to find anywhere to move it to and is now dreading the arrival of the bailiffs.

Martin Humphries, who has helped to administer the collection for the past 25 years said yesterday: “Ronald doesn’t want to talk about it at all but the worst-case scenario is that we are completely homeless at the end of the month.

“The collection is seriously under threat and we don’t honestly know what’s going to happen.”

The current museum is not exactly accessible, tucked away off a backstreet near Elephant and Castle in what was once part of a Victorian workhouse. Visitors, by appointment only, skirt round a condemned nursing home and walk up a path of broken paving stones to a peeling front door with no buzzer.

Tate Modern it is not.

The museum receives no public funding and is kept afloat by revenue from the Ronald Grant Archive — more than a million film stills that media organisations around the world pay to use. They are cross-referenced with the help of index cards.

Mr Grant is 71 and wears a leather jacket, black Levi’s, two rings through his right eyebrow and a metal stud in his chin. The film stills are the money-making part of his collection but it is the process of cinema-going, not the films, themselves that really fascinate him. Every inch of the building’s 10,000 sq ft is stuffed with artefacts evoking the era from the 1920s to the 1950s when Britons would often visit their local Picture Palace three times a week.

He began collecting as a child when he learnt the basics of the projectionist’s craft in the village hall at Banchory. At 15 he moved to Aberdeen, 18 miles away, and became a projectionist’s apprentice. He spent nights off touring rural communities in a van showing “North By Northwest, Dean Martin and Jerry Lewis — whatever was on release at the time.”

In the mid-1960s he arrived in London and after an unhappy stint at the British Film Institute, dropped out. By the late 1970s he was squatting in Brixton but the sale of a house gave him enough money to start collecting seriously in the early 1980s.

He now has tens of thousands of books and magazines devoted to the cinema industry, a collection of film posters and two rooms stacked to the ceiling with canisters of film, including adverts, trailers, B-movies, public information films and newsreels.

Elsewhere uniforms jostle for space with seats, mirrors, bits of carpet, lights, projectors and category boards that announced the screening times and ratings of the films inside the cinemas. One, from the Castle Cinema in Egremont, Cumbria has the long-forgotten H rating for “horrific”.

A sign from the silent era proclaims: “No shouting or whistling allowed — applaud with hands only. In the interest of public health please do not spit.”

Mr Grant said of his collection: “I think it is a fabulous resource. But I don’t feel that other people can see the cultural value of it, particularly the film establishment who wouldn’t care if it all disappeared.” He is finding the uncertainty “very stressful”.

“I think it’s shortening my life. I can’t sleep and I don’t think we can afford to rent storage while we wait for a new home to come up. That would kill us.”

Two possible sites for the museum have been identified in outer London but neither is likely to be available for at least two years and the lease expires on March 25.

Last night South London and Maudsley NHS Foundation Trust said that the building needed maintenance and would be placed on the open market so that proceeds from the sale could be used for mental health services.

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