A 14-year-old boy has been charged with a terrorism offence after police discovered an alleged plan to target two London mosques that was linked to “extreme right-wing terrorism”.

The child was initially arrested at an address in south London on suspicion of criminal damage to a vehicle, but officers found “a number of documents of concern”, the Metropolitan Police said.

He is accused of planning to target the two places of worship in Sutton and has been remanded in custody.

He is due at Westminster Magistrates’ Court on Thursday charged with preparation of terrorist acts on or before 9 July, and racially aggravated damage to property, the force said.

Det Ch Supt Nick Blackburn, in charge of local policing for the south London area, said: “These charges come just days after 12 people were arrested for a suspected threat to an Islamic festival in Suffolk and a man was arrested for an alleged assault outside a mosque in Leyton.”

He added: “We should not underestimate the cumulative impact of incidents of this nature on the Muslim community.”

Cdr Helen Flanagan, head of Counter Terrorism Policing (CTP) London, said it was a “very serious terrorism charge against a young boy” and “particularly concerning” to the Muslim community.

She said they were seeing an increasing number of children and young people in their casework.

The Met said it had been working closely with counter terrorism teams on the probe and had increased patrols in affected areas.

There is not believed to be “any enduring or wider threat” and police are not seeking anyone else in connection with the incidents, a statement said.