GIANT sleepless slugs could cause devastation to the county's gardens, a conservation charity has warned.

The charity BugLife has revealed last year's wet summer followed by one of the warmest winters on record has helped create a generation of sleepless slugs.

While normally the invertebrates hibernate during the cold weather, this year their population could grow by 10 per cent because they have been feeding and breeding through the winter.

The slugs are also bigger because the mild winter has improved their food supply.

Slugs are estimated to cause about £8m of damage to vegetable crops each year.

Buglife chief executive Matt Shardlow warned the increase in "super-sized" slugs could "devastate" Britain's gardens.

He added: "Due to climate shifts, warmer winters and wetter summers, we're seeing slugs become active all year round.

"Whereas key predators like amphibians will only lay their eggs once a year, slugs are not so restricted.

"Coupled with the fact that general slug varieties are also reaching full size earlier than ever, gardeners are simply not getting any respite and need innovative management solutions.

"The impact of super-sized, sleepless slugs could spell devastation for our gardens this summer."

The average British garden usually has as many as 20,000 slugs - with the gastropods laying as many as 200 eggs per cubic metre - but Buglife predicts this number could increase by 10%.

Many slugs help condition soil by breaking it down and eat decaying plants, but others feed on fresh leaves and are regarded by gardeners as pests.

December last year was the warmest since records began in 1910, with temperatures around 7.9C (46F).