I don't support gun control, but with the guy driving around, I'm not sure an armed citizen would have done much good in this case, unless he is a very good shot. He covered a fairly large area in his car, too.
The british should be prepared for this type of thing, though. People go nuts once in a while, no matter how strict the gun control laws are. I know they are not an evil people by nature, like the austrians :D,but
they need to be prepared to take out the wackos when necessary.