But the problem Blackjack is that these are not news reports about government policy or how policy is driven in the UK, most of them are the views of private citizens.
On the given right to defend yourself, a knife isn't really that useful for self defence. If you're against an unarmed attacker, then it's HIGHLY improbable that you'll be able to argue reasonable force in self defence, and if they've got a weapon it's HIGHLY unlikely that you'll be able to free and use your own knife before you've been seriously injured. You also have the added complication of risking being stabbed with your own knife.
Why can't we carry knives? Well, because if you've got a knife then you're likely to use it. Fights over spilled drinks would routinely lead to fatal stabbings. That's hardly desirable, is it?
You haven't been able to carry a gun for self defence in Britain since I believe 1928, and gun crime has only become a problem in the last 5-10 years, so it's probably not our firearms laws that are the problem.
As for your statistics, A) gun crime in Britain is so low that it wouldn't actually take a big increase in the number of crimes to crate a 50% increase and B) New York has less violent crime than London IF you count bar fights the same as fatal shootings.
I work in the ER of our equivalent of a county general, and in the last 4 years I think we've had 3 fatal stabbings and 2 fatal beatings through the department. In total I've seen less than 20 stabbings, and half of them have been self inflicted. Compare this with the experiences of one of my American counterparts, and the difference will be stark.
Finally, I really object to someone from a country with an appalling record of civil rights abuses against it's own people, where the majority feel afraid of the police, that executes more people than the rest of the developed world put together, THAT HAS THE PATRIOT ACT!!!!!!!!getting on their high horse and making superior statements about the civil libertoes and protection that I actually have more of.