I was intrigued to read this article in The Daily Mail. I think we all dislike slugs in our garden but this variety also eats agricultural crops that native slugs leave alone. if you spot them in your garden notify slugwatch.co.uk :

'Scientists are appealing to the public to help track down a giant slug which has been invading Britain from Spain.

The Spanish slug is thought to have arrived here on salad leaves but has bred rapidly - laying up to 400 eggs each - threatening British crops.

'The invasion has been slowed by frosts in May which killed thousands of them, but scientists are so concerned they have launched slugwatch.co.uk and are asking the public to help track them.

Read more: http://www.dailymail.co.uk/sciencetech/article-2457372/Scientists-plea-eradicate-giant-Spanish-slugs-UK.html#ixzz2hlzuIn51