No, it is not criminal to want real gun control, as opposed to actually banning guns for all but a very select few, as proposed by MMI. Gun control means just that: controlling who can own firearms. But limiting it to only the military, some police and a few farmers is not control, but banning. That leaves the average citizen without any means of self defense other than their hands and edged weapons. And from articles I've seen, in England it is illegal even to use those. Self defense, it seems, is against the law there.
One has to remember that any law, whether to ban weapons or to prohibit jaywalking, are only effective when people obey them. Criminals, by definition, do not worry about breaking the law. They do it as a matter of course. So believing that banning guns will result in eliminating those weapons which criminals have, or may have, is naive at best. All that does is reassure the criminals that their victims are unlikely to have any means of protecting themselves, thereby making it easier, and safer, for the criminals to do their things.