There's an interesting article here:
https://www.bbc.co.uk/news/articles/c6p20dl71jpo
"But they also say counter-terrorism forces are now battling a wide diversity of threats - including from a worrying number of people who don't support an underlying ideology, but are simply drawn to violence.
Young people being attracted to online extremism through conspiracy theories, the actions of “hostile states” such as Russia, and the “toxicity of our political environment” are also of concern, they warn."