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Long-distance swimmer encounters masses of jellyfish

30 July 2013 Last updated at 11:00 BST

A British man attempting to swim from Lands's End to John O'Groats is picking his way through large blooms of jellyfish, whose numbers are thought to have been increased by warm weather.

Sean Conway, who is currently off the coast of Wales, is attempting to swim the length of Britain. He has recently been filmed swimming amongst them.

The long, cold spring meant there were very few reports of jellyfish before June.

The Marine Conservation Society now says several species, including the Lion's Mane, are being reported in rapidly growing numbers.