Perhaps the most obvious reason is computer-generated fatigue. For the crucial core audience of 15 to 24-year-olds the adrenalin rushes are beginning to feel as synthetic as the images themselves. After years gorging on Star Wars and watching Tom Cruise blasting his way out of another science-fiction nightmare, even the heartiest fairground appetite begins to wane.

No one denies that CGI effects are responsible for some of the most spectacular monsters of the 21st century. The Lord of the Rings is a masterclass in how seamlessly these creations can be absorbed by a work of epic imagination. But respected auteurs such as Woody Allen are increasingly cynical about Hollywood’s insatiable appetite for CGI. “All new young directors are smitten by what they see, and they are smitten by special effects and blockbusters, ” Allen said. The most sophisticated prop in the business is in danger of turning into a hollow crutch.

It’s hardly a state of emergency. We still spend nearly four hours a week watching movies, which I imagine is three hours and 55 minutes more than we spend behind a Hoover. But the industry is right to worry. The most lucrative audience is still the 18 to 24-year-olds who watch on average 15 films a year.

But the dramatic decline of ticket buyers over the age of 25 reveals some shocking statistics. A whopping 38 per cent of 45 to 54-year-olds don’t go to the cinema at all. That average rises to 53 per cent for 55 to 64-year-olds, and 71 per cent for the over-65s. This can’t be pinned on the price of cinema tickets alone. Roughly half the population think that the cost is reasonable.

The biggest thief of cinema seats is the predatory DVD market. The speed at which major studio pictures are repackaged as DVDs has shrunk from six months to a matter of weeks. Increasingly, more money is spent marketing the release of the DVD than on the big-screen opening of the film itself. The convenience of DVDs is a given, and audiences are prepared to wait. Going to a multiplex is not the sexiest date for over-25s, and it’s nearly anathema by the time you hit 40.

There are other lifestyle reasons why high street cinemas are leaking customers: everything from the soundtrack being too loud to the preposterous price of popcorn. The Prince of Wales, who falls into the 55 to 64 age bracket, blames the clutter of modern life that makes doing the simplest things that much more complicated — from trying to book tickets online to juggling the bank manager, the plumber and the kids. Theoretically technology has made life ten times faster, but finding three hours to go to the cinema is an increasingly tedious obstacle course when you are over 34. The Prince, of course, belongs to that postwar golden age of filmgoers who would frequent the local fleapit on average at least once a week.

But there is arguably a more fundamental reason why audiences across the spectrum are falling out of love with their Odeons and Vues, and it has to do with the alarming reliance on blockbusters to sell seats. That simplistic studio philosophy is now clearly open to question. The lack of variety needs to be addressed if cinemas are to rekindle their magic pulling power on the over-25s.

I’ve noticed in the past three years an increasing appetite among more mature audiences for feature-length documentaries, script-led dramas and high-wire stunts without a digital pixel in sight. But they are rarely distributed outside Britain’s major metropolises. The big cinema chains have to stop stacking their chips on the next Harry Potter and widen their horizons, or they will merely confirm cinema as the segregated culture it is apparently becoming.

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