The teenager, from Darlington, County Durham, pleaded guilty to three counts of possession of a record of information likely to be useful to a person committing or preparing an act of terrorism.

He appeared at Westminster Magistrates' Court on Tuesday. The offences are related to extreme right-wing terrorism, police said.

The boy was arrested when he was aged 13 in July last year, as part of a planned operation by Counter Terrorism Policing North East.

He cannot be named because of his age and will next appear at Newton Aycliffe Youth Court for sentencing on 1 April.

Before this case, the youngest defendant to be convicted of terrorist crimes was a 14-year-old from Blackburn, Lancashire, who can only be identified as RXG and who plotted to murder police officers in 2015.

He sent encrypted messages instructing an Australian jihadist to launch attacks and was jailed for life in October 2015 after admitting inciting terrorism overseas.

Last year, the Parole Board ruled RXG could be freed from prison under strict licence conditions.

His identity will remain a secret for the rest of his life after a High Court ruling in 2020.