Several hundreds of dustbin lid-shaped jellyfish washed up on the beaches across the South West.

Area officials said that the jellyfish were found covered with sands at Cefn Sidan sands in South Wales and at Dawlish Warren on the south Devon coast.

They advised the beachgoers not to touch the specimens despite knowing that they can cause no harm to humans, as it can leave a sting similar to that of a nettle.

The jellyfish at Dawlish Warren were at first photographed by Claire McDonald who was shocked to find the shore covered.

She said she counted at least 130 and they stretched as far as she could see along the beach. They were evident as far as the eye could see.

Beachwalker Sarah Harrison, 22, reported an incredible sight like something from a sci-fi movie as she made her way along Cefn Sidan sands.

Rory Dickinson, countryside manager for Carmarthenshire council, said, “Their numbers have increased this year partly due to the warm spell and the changing chemicals in the sea. They're generally harmless, lead amazing lives and are a vital part of our wildlife”.

Experts said that the warm weather has sparked a boom of the creatures, which can grow up to 35 inches in diameter. They said that the number has grown in recent years because of mild winters allowing plankton to thrive.

The jellyfish that washes the British beaches are so plentiful that fishermen are complaining about the numbers being hauled up in their nets.

Conservationist Steve Trewhella, 51, of Wareham, Dorset said this year's invasion of jellyfish as unprecedented.

The barrel jellyfish are the largest species that are found in south-west England. The species is not rare in UK but are more often seen washed up on beaches and it is unusual to see more than one bobbing along in the water.