After using Google Earth to find houses with plush swimming pools would-be revelers are inviting hundreds of strangers, via Facebook, to impromptu pool parties.

The latest craze know as 'dipping' has already seen homeowners wake to find their private pools filled with beer cans.

Police say groups have been found on social networking sites Bebo and Facebook organizing the parties and inviting up to 500 people.

The sites say party-goers should attend in fancy dress and bring a bike so they can get away quickly if discovered.

A spokesman for Devon and Cornwall Police said yesterday: 'We are advising owners of swimming pools to be on their guard.