A teenage boy has been arrested on suspicion of a terror offence.

The 17-year-old was stopped by police when he returned to the UK on a flight into Gatwick airport on Sunday.

The Met Police’s Counter Terrorism Command stopped the teen under schedule 7 of the Terrorism Act 2000, which gives police unique powers to examine people who pass through the country’s borders.

Officers examined his phone during the stop and he was subsequently arrested on suspicion of dissemination of terrorist material.

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Commander Dominic Murphy, head of the Met's Counter Terrorism Command, said: "We work closely with other partner agencies to monitor our ports and borders and the powers available to us under schedule 7 help us to keep the UK safe from potential terrorist threats.

"This is also another example of a teenager being arrested for terrorism offences and it is a concerning trend that we have been seeing for some time. Our message to parents, carers, friends and family is that if you have any worries or concerns about a loved-one being radicalised or drawn into extremism or terrorism, then please act early and get in touch so that we can help before it could be too late.”

The 17-year-old boy was interviewed at a London police station and has been released on bail until a date in July, the Met said. The investigation relates to extreme Islamist-related material.

As part of the investigation, officers have also carried out a search at a residential address in south west London and enquiries remain ongoing.

A Met spokesman said: "Anyone with concerns about somebody who may be vulnerable to radicalisation can visit the Act Early website www.actearly.uk where there is advice, guidance and support available. This includes information on the warning signs to look out for, as well as tips about what to do and what not to do if you think somebody may be being radicalised.

"You can also call the Act Early Support Line between 9am and 5pm daily on 0800 011 3764, in confidence, to share your concerns with our specially trained officers."