By Camilla Turner Daily Telegraph 11th March 2015.

Britain must brace for a bucolic invasion as millions of slugs and snails, led by the cannibal Spanish breed, are set to swarm gardens across the country, a new report warns.

Experts predict that this will be the worst ever year on record for the slimy garden pests due to a particularly warm winter, with above average temperatures recorded for December and January.

Dr Ian Bedford, Head of Entomology at John Innes Centre, has estimated that a cubic metre of garden in Britain could have to accommodate up to 200 slugs, each of which can have up to 200 offspring.

"They usually survive the winter in our gardens as eggs,” he said.

“Without a cold snap, it's fair to say that slug numbers, especially the invading Spanish slug, which can lay up to 400 eggs, will escalate this year.

"So don't be surprised either if you spot gardeners out at night, headtorches and all, tracking down slugs in their gardens."

Slug experts have warned gardeners that the generally mild winter temperatures will cause a slug and snail "population explosion", allowing them to cause devastation in their wake.

While gardeners can humanely remove native British slugs by releasing them into the wild, experts say that Spanish Slugs could have a potentially damaging effect on the environment they are released into.

The numbers of voracious Spanish slug are set to escalate this year following a breeding "frenzy" over winter.

It reproduces at twice the rate its native British counterparts, which are hermaphrodites, and can grow up to 15cm in length.

The Spanish invading species also has extra layer of protective slime, meaning it is immune to most common pest control products.

Dr Bedford said gardeners should also encourage natural predators, such as birds and hedgehogs, into their garden, helping to keep their slug infestation down as well as helping to protect native British wildlife.

Double trouble: Spanish slugs can lay two times more eggs than UK varieties (Wolfgang Fischer)

Last year gardeners removed up to 4,000 slugs a month and spent £11.6 million on products attempting to remove them.