Holidaymakers have been warned to watch out for a giant swarm of jellyfish that has invaded the Mediterranean.

Beachgoers in France, Spain and Italy could be hit by the stingers.

In a single day, paramedics treated 500 jellyfish stings along a ten-mile stretch of beach between Nice and Cannes on the French Riviera.

The emergency services even had to rescue a group of youngsters who became stranded on a raft surrounded by the creatures.

Booms and nets have been put in place and a special "jellyfish hoover" boat has been sucking them out of the water.

Spanish beaches are being hit by the Portuguese Man O'War, whose sting can be fatal, while the mauve stinger, which can leave permanent scars, is menacing the south coast of France.

Although the plague is concentrated in the Mediterranean this summer, last November there was a "vast bloom" along the north west coast of Britain.

The Marine Conservation Society is asking visitors to the coasts to help map where and when different types of jellyfish are popping up.

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