If someone is not born in the nation and has refused to embrace the nation as its own.
If they openly harm/plan to harm: people, property, or the integrity of the nation.
If they are using the nation as a stronghold to continue or bolster the war efforts in their nation of origin.
Than they should be sent back to their nation of origin and not be allowed to return. They are obviously not citizens, they are just using the nation to supplant their own agenda and it needs to be stopped. The only reason its allowed to continue is because people are too blind, ignorant, and politically correct to stand up and stop the surreptitious invasion. Look at France for crying out loud
I think that when an extremist lives in a country and chooses to behave in a way that encourages violence and anarchy towards the government in where they live, then the government should have the right to expel and send extremists into exile. I think the UK would definitely benefit from expelling the extremists.
If you have individuals willing to do harm to others or themselves it may be prudent to remove them and send them from whence they came. Of course the accusation of extremism is not enough, If someone takes extreme measures, damaging property and hurting people they should be expelled. Of course you are turning an extremist out into their home country or making it someone else's problem. If the crime is extreme enough they should answer for it qat some point.
By acting to try to eliminate all threats against the homeland, the UK would be inviting too much hatred and criticism by attempting to expel or exil extremists. Perhaps a sense of injustice or false accusations would ruin the nation's credibility, while options that include domestric protection including options like imprisonment would be better suited.
No what does that really achieve? This does not achieve much at all in this type of thing. Sending them to exile only hurts the United Kingdom and it will cost the Queen even more money to do this. How dare we touch the royals money and their popularity and everything else.
No, they do not need to get rid of extremists at all, because it is a democracy over their, so they need to have the right to voice their opinions as much as they want, and no one should be able to tell them if they have to leave or not.