Next they will mandate everyone eats with their hands, no more knives, forks spoons or even chopsticks.
And at some point they're just going to have to ban people from ever leaving their home. Then they will have to mandate that people live alone in their home. Then they will mandate that the people put up bars surrounding their homes to keep people out. And at some point the people of England will realize they have allowed their government to imprison them.
While the point that there is always another weapon is valid, the bigger issue is that banning guns does not actually get rid of guns. It merely means only criminals will have them.