The Mayor of London's office has been forced to remove promotional material for its anti-knives campaign after it was discovered celebrity endorsements supporting the drive had been faked.

Star Wars actor John Boyega, grime artist Lethal Bizzle and singer Jessie J were among those who featured in the information pack apparently endorsing the London Needs You Alive scheme, launched by Sadiq Khan in November last year.

But it has since emerged that the entertainers were not consulted about their involvement, and that the social media posts featured - including content from Twitter and Instagram - were fake.

One, featuring Peckham-raised actor Boyega's Twitter handle, made play of his recent role in the sci-fi blockbuster, claiming: "The force needs me alive, so I don't carry a knife. Share why #LondonNeedsYouAlive #LNYA".

Another, attributed to @LethalBizzle, said: "Grime needs me alive, so I don't carry a knife. Share why #LondonNeedsYouAlive #LNYA."