For a while, the UK has had a rule that you can only legally carry a folding (non-locking) blade of under 3" without good reason. (Actually, the law says you can't carry anything sharp without good reason, but that a small, SAK type folder is generally acceptable without a specific reason.) There is a degree of leeway that is at the discretion of the police and the prosecutors (something like the Spyderco UK penknife is fine if you are in the woods, not in a city centre bar at 11pm I suspect!)

But recently there were a series of stabbings which caught the press (who then put the usual incidents front page to create an impression of increasing rates). There is also a rise in young people carrying knives to school. And, as I'm afraid is often the case, the politicians decided to be seen to do things rather than solve the problem. So they had a knife amnesty, where people handed in hundreds of souvenirs, unwanted kitchen knives etc. But as you can still buy knives - the amnesty missed it's point.

I don't mind the knife law particularly (an SAK on EDC and other things with reason) although I'd like to be able to carry one that locks. BUT I do object to the utter failure of the powers that be to tackle the problem. As ever, those of us that are law abiding comply to new laws, and lose out, and those who are by definition outlaws ignore it and carry on.

(As an aside, I think some of this stems from the decline in hard contact sports in schools-it used to be that you could prove how tough you were instead of pretending by carrying a knife)