Take their guns. Take their knives. Then also demand to continue taking in the very people using the guns and knives to wreak havoc on the law-abiding people of that same city while leaving Londoners defenseless against attack.
It is madness how the once-proud Brits have allowed themselves to be made fools of by globalist operatives like Sadiq Khan who has been pushing for enhanced Muslim immigration into Great Brittain for years even as that immigration has created a shocking increase in violent street crime by extremist Muslims. The same increase in violence is taking place throughout Western Europe and Canada and should these globalists have their way will be coming soon to an American city near you.