Peace lovin' tree huggin' hippy says..... no
Probably not a huge suprise there
Trouble with national service ideas at the moment is that you're quite likely to get deployed. And deployed you stand a chance (thankfully still quite small but definitely significant) of coming back in a body bag or missing some limbs. And that then raises the penalty for any given crime from "X months/years in prison" to "death penalty". Which, you'll not be suprised to learn, also doesn't sit too well with peace lovin tree huggin free lovin hippies
Secondly, sticking crims on active service does nothing for the safety, wellbeing, or moral of regular law abiding volunteers they're fighting alongside.
On the knife crime "epidemic" it's worth noting that if you remove London from the figures then knife crime is very rare - something like 40% of all assaults with knives are in London - ergo this isn't a "national epidemic" but rather an inner city problem affecting the capital. Teen on teen violence, guns and knives taken together, is actually pretty much static. These two bits make interesting reading -
http://www.bbc.co.uk/blogs/thereport...and_teens.html and
http://www.bbc.co.uk/blogs/thereport..._epidemic.html
The major problem in drawing up legislation to combat knife crime is that knives are just damn handy tools to have around. It's so hard to define what is and what isn't a reasonable requirement to carry one. Even excluding cooking I probably use one daily, whether it's getting through parcel tape or stripping wires. I keep a swiss army knife in the car glovebox and tend to keep one on the bike too. They're unlikely to be needed but it's not unimaginable that they'd be needed and in the past they have indeed come in handy.