extremism is "the promotion or advancement of an ideology based on violence, hatred or intolerance, that aims to:

1. negate or destroy the fundamental rights and freedoms of others; or

2. undermine, overturn or replace the UK's system of liberal parliamentary democracy and democratic rights; or

3. intentionally create a permissive environment for others to achieve the results in (1) or (2)" https://www.bbc.com/news/uk-68564429