The UK and Guns

So lets face it, the UK has some serious issues with guns. We know for a fact that firearms are illegal in the UK (perhaps a commendable attempt at peace). However, time and time again, we have seen that even law enforcement has been known to act stupidly around firearms in the UK. Let me just say this. Recently there have been many uprisings in the UK over a single incident involving an escaped convict and the police who killed him after a three hour negotiation. The defense that people have put out is that "he was just a boy! They killed a poor boy! He didn't know what he was doing."
The man in question was a 29 year-old adult male, just a month short of turning 30. No 30 year-old person I've ever known considered themselves a "kid" anymore. In fact, in the United States, any person, regardless of sex or race, becomes a full fledged adult at the age of 25. You can smoke, drink, rent a car, hold a job, fly all over the world without an escort, get a permit to own and use a gun, fight and die for your country, look at porn, and go to any movie you damn well please. The only things you can't do at that age are climb the political ladder. So tell me, Britian. Do your citizens only become adults when they start to climb over the hill at 40? Because, regardless of what you say, that 29 year-old man was an adult. He knew the laws and knew damn well what was expected of him to not break them. If a man is old enough to fight for his country, he's old enough to think for himself, period.