More than 500 jellyfish sightings have been reported by the public on Cornish beaches this summer.Getty

Cornwall tourism bosses are desperate to reassure holidaymakers that the surge in the number of jellyfish sightings on beaches "poses no danger".

Particularly warm currents around the UK's south-west coast have brought swarms of jellyfish to the area, including the Barrel jellyfish which, though harmless, is a staggering one metre in diameter.

According to data released by the Marine Conservation Society, there has already been more than 500 reported sightings of individual and swarms of jellyfish in Cornwall this summer, compared to just 1,133 sightings in the whole of 2013.

Jellyfish numbers are expected to rise further, sparking fears that people will be put off visiting Cornish beaches.

Malcolm Bell from Visit Cornwall told Sky News: "It's no different really to rock pooling – you keep your eyes open for the crabs and everything else.

"It's part of the habitat. It's part of the fun thing about having a British beach holiday."

Scientists at the University of Exeter charged with examining the jellyfish data say the number spotted is dramatically higher than when the study began nine years ago.

The public have even reported sightings of the infamous Portguese Man O'War. This jellyfish carries a very nasty sting, although it is far rarer than commonly sighted breeds such as the Moon jellyfish.