A teenager has been found guilty of planning an Islamic State-inspired terrorist attack on a pop concert a month after the Manchester Arena bombing.

The 17-year-old, who is of white British heritage, researched security surrounding a Justin Bieber concert in Cardiff and wrote a “martyrdom letter”.

Fearing he was about to strike, police raided the boy’s home in the south Wales valleys on the day of the show and found a claw hammer and a gutting knife in his school rucksack.

The suicide note read: “I am a soldier of the Islamic State. I have attacked Cardiff today because your government keep on bombing targets in Syria and Iraq. There will be more attacks in the future.”

Jurors were told the boy had also written a note with bullet points including “run down the non-believers with a car” and “strike the infidels who oppose Allah in the neck”.

The defendant, from Rhondda Cynon Taf, denied preparing for an act of terrorism, two charges of encouraging terrorism online and two charges of possessing editions of an Isis propaganda magazine.

He told the jury at Birmingham crown court that he had a “stupid interest in the gory” and was curious about Isis but claimed he had no intention of carrying out a terrorist attack.

In the witness box he said he did not possess a copy of the Qur’an, did not believe in Islam and ate ham.

Insisting he was merely curious, he told the court: “I wanted to see how easy it was for people who had an interest in terrorism to go online and get information because the police and the government are trying to crack down on terrorism and radicalisation. I wanted to see if it was possible, not for me but from someone else’s point of view.”

His defence counsel, Delroy Henry, likened the youth’s interest in Isis to rubberneckers on a motorway. “He was drawn into it, curiosity getting the better of him,” Henry said.

Police raided the boy’s home on 30 June 2017. He surrendered his phone and told police his Instagram password was “TruckAttack”. Officers carried out a “safety interview”, which allows questions to be asked without a lawyer being present.

The boy said he had been talking to someone on Instagram calling themselves Al-Baghdadi for about a week. That person had told him he would go to hell because he did not believe in Islam and he needed to perform an act of terrorism if he wanted to go to paradise. The jury was told that the leader of Isis is Abu Bakr al-Baghdadi.

The defendant said: “They started telling me about, instead of living your life like a good Muslim … basically kill people who don’t believe in Islam, because one day there will be more Muslims than Christians and Muslims, Islam will dominate the world.”

He accepted in this interview that he had posted material on Instagram about an attack on Cardiff but claimed he had not meant any harm. He also conceded he had put the hammer and knife in his bag and had taken it to school that day, but he claimed to the police that he had not intended to use them to attack anybody.

The boy said: “I never thought about actually doing it. Even though I did carry a hammer and a knife I never thought about doing it for one minute.”

When police investigated his internet history they found his interest in Isis appeared to have begun a year before, in June 2016, when he searched for details about the Isis fighter known as Jihadi John.

In the coming months he researched information on attacks in London, France and Germany. On the boy’s laptop police also found copies of an Isis propaganda magazine that gave details of how to carry out knife and vehicle attacks.

By June 2017, the defendant was posting images of terrorists, pictures of the Isis flag and images encouraging a terrorist attack on Cardiff via an Instagram account called “Alqaeds”.

He searched “17-year-old jihad” and “vehicle mounting pavement – car ploughs through a crowd”. He appeared to be searching for a target, looking up the New Theatre in Cardiff, Cardiff Central Library and the McArthurGlen outlet centre in Bridgend.

In the days before the Bieber concert at the Principality stadium, he searched for information about the event. The following day he searched for “Justin Bieber security”. Other search terms included “how to steal a car” and “how to steal a car from a non-believer”, and he also visited a web page describing how to kill someone with a knife.

Remanding the boy, who cannot be named because of his age, in custody until a sentencing hearing on 10 January, Judge Mark Wall QC told his defence barrister, Delroy Henry: “The offences for which he has been convicted obviously merit a significant custodial sentence.

“One of the things I will have to consider is whether there ought to be an indefinite sentence. I need as much information on him as you wish to place before me.”

The court heard that since being charged the boy had received a diagnosis of autistic spectrum disorder, although it was not said to have affected his ability to make decisions.

Sue Hemming, from the Crown Prosecution Service, said: “This teenager’s behaviour over many months leaves no doubt that he intended to kill and maim as many people as possible in an attack reminiscent of the incident on Westminster Bridge.

“The CPS presented overwhelming evidence that he was prepared to die for [an] extremist worldview and he will now rightly face the prospect of a substantial prison sentence.”

The jury was not told how the teenager was caught. But outside court, DS Lee Porter, of the Welsh extremism counter terrorism unit, suggested friends may have contacted the authorities.

“This case has highlighted the ongoing concerns with young people gaining access to extremist material on the internet and how quickly that can lead to radicalisation. This individual actively sought out that material,” he said.

“As he became radicalised his behaviour became a concern. Friends were aware that he was displaying extreme views and he had possession of a knife in school.

“We would urge people to speak to a family member, teacher or us so that we can intervene at the earliest opportunity to keep the public safe. You will not get into trouble by reporting concerns.”





