Rediscovered, the film that 'proved' Nessie exists

A flickering ballroom black and white image lasting less than 60 seconds but which spawned a multimillion-pound international industry has been rediscovered after 65 years.

The original 16mm newsreel footage of a grainy dark blob causing ripples on the grey surface of Loch Ness in 1936 was hailed as "definitive proof" of the monster's existence when it was shown to packed British and international cinema audiences.

Shot by a Glasgow film maker, Malcolm Irvine, for his Scottish Film Productions Company, the footage shows a 30ft long creature with two humps thrashing about on the east side of the loch, opposite Urquhart Castle. It helped generate world-wide interest in the legendary monster which is now worth hundreds of millions a year in tourist income and spin-off merchandise to the Scottish economy.

However the film disappeared without trace when the film company went bust in the late 1930s and most film historians believed it had been destroyed and lost for ever. It wasn't until Scottish Screen Archive was trying to identify and catalogue a collection of old cans of film found in the basement of the Scottish Film Council that the footage was rediscovered earlier this year.

Now the film, The Loch Ness Monster – Proof At Last, is to be shown on television, as part of BBC2 Scotland's celebration of St Andrew's Day on Friday. Janet McBain, curator of the Scottish Screen Archive, said: "Irvine had seen the monster three years before but his camera jammed and he was determined to get it on film."

When the original film was presented to the Linnaean Society, a body which classified animals, they were unable to explain what it could be and the 20th-century myth of the Loch Ness Monster was born.

Since then there have been 27 more "sightings" captured on film, and an industry has grown up estimated to be worth £120m a year to the Highland economy and millions more to Scotland as a whole.