The so-called 'spy glasses', of which Kardashian business mogul Kylie Jenner has her own range, feature a 12 MP ultra-wide camera which allows users to record in public discreetly.

Meta says safeguards are in place to prevent surreptitious filming, but some UK venues now prohibit them from being worn at all

It comes amid growing concern that the glasses could be used to covertly film members of the public