These people will buy a knife and stab several people... they do not need millions to fund attacks. {What is the cost of a knife?.. $5?}
Oh the UK government have that covered for you, the recent rise in knife crime has prompted politicians, newspaper columnists and psychiatrists to call for a ban on knives with points. Which is very similar to what the rules are in prisons, if I understand correctly, lol.
Put more Police on the street and improve intelligence gathering and stop killing people in foreign countries.
Listen, governments don't really want to solve problems. If they were ever effective at solving problems, they would end up with no problems left to solve. Creating and perpetuating subtle problems, and then treating the consequences (instead of the cause) is how politicians stay in business. We're here (using and championing Bitcoin) because of one of the most subtle problems (propped up by politicians) that exists: central banking