Here's Rodney, with a look at Shining examples of allegory

That film was The Shining, and the kid who didn't stay in the pictures grew up to be Rodney Ascher, director of a new documentary, Room 237, which examines some of the theories about Stanley Kubrick's film.

One theory, for example, has it that The Shining is all about the genocide of Native Americans. Another argues that it exposes the faking of Moon landing footage. And there was the rest of us thinking it was just Jack Nicholson's character coming down with a bad case of cabin fever.

Ascher can still recall what gave him the heebie-jeebies in that first encounter with The Shining.

"From the opening moments of the movie it felt like this was a story with biblical connotations. I felt so dwarfed and puny compared to it." He did manage to get through it a couple of years later, though, when it came out on VHS.

He would revisit it many, many times later when it came to making Room 237, named after the notorious suite visited by Nicholson's blocked writer, Jack Torrance. At one point, such was the amount of material being marshalled to illustrate the theories, Ascher was working with a 30-page spreadsheet.

He was first put on to the theories about The Shining by his friend and producer, Tim Kirk. The two spent a year researching what was out there, and were amazed to find what a large body of work there was, from academic papers to blogs.

It was the internet, says Ascher, and new technology in general, which turned what was a cottage industry of theories into something much bigger and more accessible. DVDs allowed people to watch the film in different ways – freeze frame and slo-mo being particularly useful when crafting theories – and the internet allowed people to put their ideas out there and start a debate. "They no longer needed a publishing contract or a column in a newspaper to share their ideas with the outside world," says Ascher, 45, speaking before the documentary's London Film Festival premiere. "That really encouraged people to get active."

Having been a hit at Sundance and in London, Room 237 has certainly got people talking. It has surprised Ascher that of all Kubrick's films, it is The Shining that has prompted so much reaction. He would have expected more attention to have been paid to 2001: A Space Odyssey.

As a disclaimer on the film's website stresses, Room 237 has no links to Kubrick's estate or The Shining. Ascher doesn't know what the estate makes of the documentary, but he would like to think it would be viewed positively.

"I hope they appreciate that what we are doing is very much testament to the fact that his films continue to fascinate and inspire people, and that that level of engagement is increasing."

Some theories were rejected because they could not be substantiated, such as the one that relied on finding faces and animals in some of the shots – but only if the frame was turned sideways.

"I was happy that the people that we found came from different walks of life, some of them were more conservative, some more outrageous. Ultimately Room 237 is not specifically my attempts to explain the mysteries of The Shining, but to talk about the fact there's a lot of people who are actively trying [to do that], and isn't it interesting it is happening now."

DECONSTRUCTING modern films is harder now because most don't embrace ambiguity the way The Shining does, says Ascher, who has had "every job possible" in the film industry, from prop man to editor. What about Inception, Christopher Nolan's mind-bender? "That has inspired stuff, but not as deep as The Shining. We'll see how it looks in 30 years. Most of what I've seen for Inception are people working on the surface layer of the plot, like was he dreaming at the end or was he not."

He has seen one allegorical reading of Inception, arguing that it is about the filmmaking process. In other words, Leonardo DiCaprio creating dreams is like Christopher Nolan creating films. "That's kind of interesting but we'll see if we find four or five more competing readings. Maybe Prometheus is the contemporary one they are toying around with now."

The last film Ascher saw that puzzled him so much he wanted to see it again was Mulholland Drive, David Lynch's 2001 mystery.

After spending two years on Room 237, one wonders if The Shining wasn't becoming for him as much of an obsession as it was for the theorisers.

He laughs. "I channelled it into this film and the film is doing pretty good. Obsessions are only problems when they start to ruin your life."

For those intrigued by Room 237 and want to get in on the next big thing to deconstruct, Ascher has a tip. "Eyes Wide Shut seems to be rising in the rear view mirror."

So rent or buy it today. As Jack Torrance doesn't write in The Shining: "All viewing and no thinking makes Jack a dull boy."

Room 237 opens tomorrow