Criminalisation will prevent radicalisation by stopping users accessing the most extreme content. Sites such as YouTube and Facebook already police themselves and are unlikely to allow extremist materials to remain online for extended periods in the face of public pressure. [1] It is for extremist websites where public pressure can have no effect that needs the law to step in by punishing those who are regularly visiting those sites and being radicalised by them.  [1] Google, ‘Our approach to free expression and controversial content’, googleblog, 9 March 2012.