The number of people with autism on the UK's anti-radicalisation programme Prevent is "staggeringly high", the head of the country's terrorism watchdog will say in a speech on Wednesday.
Jonathan Hall QC, Britain's independent reviewer of terrorism legislation, will highlight a number of recent terrorism cases in the UK which have links to autistic offenders.
He will use the speech, which is part of think tank Bright Blue’s Ludgate lecture series online, to argue that more scrutiny is needed of the links between autism and terrorist activity.
"My understanding is that the incidents of autism and Prevent referrals are also staggeringly high," he will say.
"It is as if a social problem has been unearthed and fallen into the lap of counter-terrorism professionals.
"Autism has not received much public attention, and there is a very real and respectable fear that making any sort of link will lead to stigma.
"It is quite possible, and this is supported by some of the research, that the relevant factor is autism plus, meaning that for people on the autistic spectrum who are drawn into terrorist violence there tends to be some additional factor at work like a very unstable family background or some other cognitive difficulty."
Mr Hall will identify the recent convictions of Lloyd Gunton, 17, who declared himself a soldier of ISIS and had prepared a vehicle and knife attack in Cardiff; Jack Reed, who had been involved in neo-Nazism since the age of 13 and was jailed for planning attacks on synagogues in Durham; and Paul Dunleavy, 17, who was planning a far-right attack, all of whom were autistic.
He will point to the rise in the number of youngsters being arrested, citing the case of a 14-year-old who was arrested last year for researching explosives and preparing shrapnel bombs.
"This sort of arrest is happening at what appears to me to be an astonishing level of frequency," he says.
"As part of my role I am notified whenever an individual is detained under terrorism powers: this allows me to speak to investigating officers to test the investigative temperature. I have lost count of the times the detainee in a recent arrest has turned out to be child.
"Official statistics, most recently published in June, show that arrests for terrorism related activity amongst the under 18s were rare in the years 2003 to 2012, never rising above 5 per cent of the total. The rate crept up to a maximum of 6 per cent until March 2020.
"But in each of the last quarters ending March 2021 it has been between 10 and 16 per cent. The pandemic dramatically affected the arrest rates for all age categories, but not for the under 18s: here the absolute number of arrests went up. Almost half the arrests of under 18s since March 2001 have been in the last five years."
The UK runs the anti-radicalisation Prevent programme, which offers practical help to try to prevent individuals being drawn into extremism, and the Channel programme, which intervenes in cases where someone is already on that path.
When authorities decide there is a risk that a person referred to Prevent could be drawn into terrorism, they are assessed as part of the Channel scheme and potentially taken on as a case. Engagement with the scheme is voluntary and it is not a criminal sanction.
Earlier this week, occult-obsessed teenager Danyal Hussein, 19, was convicted of murdering two sisters in a London park in a satanic ritual. He had been on the Prevent scheme and had Asperger’s syndrome.
"It is possible that we are at a point where our understanding of terrorism and the terrorist threat is going to have to shift once again", Mr Hall will say in his speech.
The speech is being held to mark the 16th anniversary of the July 7, 2005, terrorist attacks on the London transport system in which 52 people were murdered.