Voters ‘used as lab rats’ in political Facebook adverts, warn analysts

Parties are all involved in a targeted experiment that campaigners warn lacks transparency and could harm democracy

The three main political parties in England and Wales are using Facebook audiences "as lab rats in a giant experiment", according to the first detailed analysis of online advertising during a UK election.

Campaign group Who Targets Me?, which was established to monitor online political ads, has been examining how parties used Facebook before the election was called and in the first week of the campaign. It has found all three parties trialling subtly different messages, images and even colours as they seek to learn what resonates with voters.