Switchblades (or flick-knives as they are more referred to over here) have been outlawed over here for a long while now - since I was a kid, I think.
And parts of the UK does seem to be undergoing some sort of knife-carrying trend at the moment - especially amongst teenagers.
http://www.bbc.co.uk/news/uk-england-birmingham-42861064
Tradesmen (or women) - or anyone with a good reason to be carrying a knife or blade (butcher, chef, carpenter, fisherman, even an IT engineer - got to cut those cables! etc) will be okay to go about their usual business.
Some overzealous copper may make things a little awkward - though common sense usually prevails on these things - especially when a more experienced officer or Sgt becomes involved.
On occasion when I’ve been asked about what I’m carrying in my IT bag it’s more a case of ‘be careful it doesn’t get nicked’ - or that ‘any blades are hidden away from kids or prying eyes’ or ‘wrap it up so you don’t cut yourself’ etc.
Whether these changes will make a difference? I don’t know - likely not for some already on a wrong path. I hope it does make a difference - and at least it seems to be a genuine attempt to curtail it, though it would be welcome if the Govt actually addressed the causes and issues surrounding this.