One of the world's most famous fables faces a serious financial test in two weeks' time when 100 international athletes plunge into Loch Ness - each insured for £1m against monster bites.

A hefty but undisclosed premium has been paid by organisers of Scotland's biggest triathlon in case the swimming stage of the event tempts the mysterious (and possibly non-existent) creature from the lake's depths.

Teams from five countries are taking part in the event and organisers, who also manage the Great North Run in Newcastle upon Tyne, are worried about health and safety consequences if the monster strikes or tries to join in.

"With so many top athletes in the water of Loch Ness at one time, we couldn't take the risk of one of them being attacked by Nessie," said David Hart of the firm Nova International.

"The competitors will all be very psyched up and very driven, so there's going to be a lot of noise and a lot of splashing going on, just the sort of thing that might annoy a prehistoric lake monster. Or even worse, give it an appetite."

The swimming stage of the race, the Visit Scotland Adventure Triathlon, will see athletes swim twice round Urquhart Bay, the setting for many of the most famous sightings and photographs of the alleged beast.

The race also takes in an 11.8 mile afternoon bike section and an evening run along a 6.2 mile mountain trail.

Not everyone welcomes the insurance deal, though. The official Loch Ness Monster Fan Club took exception to the suggestion that Nessie would attack anyone - however much they splashed.

The club's chairman, Gary Campbell, said: "Everyone knows she is friendly; she has been present in the loch for centuries and never hurt a soul in all that time.

"If she wanted to get involved in the race, though, that would be another matter. Through her knowledge of the loch, she'd beat everyone. She might even continue on land and finish the competition, though I doubt that."

The insurance cover will include accidental damage from the monster nipping human competitors or shoving them aside if she, or he, does decide to join in.

David Parker, the head of commercial insurance at NIG, the firm providing the policy, said: "From an insurance perspective, this is a very unusual risk and a lot of insurers wouldn't want to deal with it."

Claimants, he said, would have to provide definite proof that the monster was responsible.