Hope Not Hate estimates that up to 60 people are active in neo-Nazi networks
https://www.independent.co.uk/news/uk/home-news/islamist-extremists-uk-highest-number-europe-25000-terror-threat-eu-official-isis-islam-britain-a7923966.html
https://www.independent.co.uk/news/uk/home-news/far-right-neo-nazi-uk-extremism-children-teenagers-report-hope-not-hate-a8781941.html