Originally, the suspect was arrested for damaging a vehicle, but during a search police allegedly located plans to attack two mosques in the Sutton area, in South London.

British police arrested 12 people over a suspected far-right terrorism threat targeting an Islamic event attended by about 15,000 people.

The child, who cannot be named for legal reasons, was initially arrested on Thursday on suspicion of criminal damage to a vehicle in the Sutton area.