The judge at the Old Bailey has adjourned the sentencing of 19-year-old Matthew King from Wickford in Essex.

He was put under surveillance after his mother raised concerns that videos he was watching promoted hatred.

Judge Mark Lucraft KC said she had "done exactly the right thing".

King pleaded guilty in January to the preparation of terrorist attacks between 22 December 2021 and 17 May 2022.

At Friday's sentencing hearing in London, the prosecution outlined the case and the defence began its mitigation, however the judge adjourned the hearing for two weeks for further inquiries to be made at the prison where King is being held.

The court heard that intelligence reports from the jail suggested King had said he would "behead the imam".

King's barrister Hossein Zahir KC said this was "a throwaway remark by an angry young man being stuck in his cell" and asked for further inquiries.

'Immodest'

Earlier, the prosecuting barrister Paul Jarvis told the court King had dabbled in drugs since early secondary school, was expelled and left education at 16 with no qualifications.

He said King converted to Islam in 2020 and, at first, his behaviour improved, but in 2021 he began criticising his sisters' clothing as immodest and attended mosques wearing combat clothing.

He was put under surveillance after his mother reported him to the government's anti-extremism agency Prevent, because she feared some of the videos he was watching promoted hatred.

Several of the mosques he attended also warned him about his behaviour, and one decided he was no longer welcome, Mr Jarvis told the court.

In 2022, in the weeks before his arrest, King began carrying out reconnaissance in east London, including on police officers patrolling outside Stratford railway station, as well as at Stratford police station itself and the local magistrates' court.

Mr Jarvis told the court that one of the videos found on his phone featured footage near the police station, overlaid with a soundtrack including the words: "Coldly kill them with hate and rage. Plan your perfect killing spree."

On 17 May 2022, a CCTV camera captured him filming after dark outside a 7 Rifles Army barracks in east London.

He was arrested at his home the following day and his phone examined.

CCTV showed King filming outside an east London barracks

Officers found Snapchat messages King sent to a girl who was still in the sixth form, known in court as Miss A, in which he said he wanted to travel to Syria to become a martyr.

They exchanged messages about how they would like to mutilate members of the British and American armed forces.

Miss A wrote to him: "We can't let them die quick tho. Slow painful death akhi... I'll guide you through it. Or bring him or her home."

The prosecution said King had said he was "training for Jihad" and just wanted "to kill people".

Mr Jarvis told the court that on 17 May 2022, the day before King's arrest, the girl messaged him to say she wanted to concentrate on her exams.

King replied to say he would "be worshipping Allah" and he might soon be "on the news".

The sentencing has been adjourned until 26 May.