I suppose that TOR is used a lot by dodgy folk just because it's such a good tool at what it does - it's a bit like saying that body armour is used by a lot of dodgy people, but that doesn't make body armour intrinsically evil in and of itself, and you certainly shouldn't be busted for owning/wearing it.

As for getting busted for something and the UK police finding that you'd been using TOR - I wouldn't worry about that, as their tech competence is piss poor, and getting a judge and/or jury to understand it would be an undertaking and a half.

Worryingly enough, though - there is a law in the UK that came in a couple of years back - I forget it's acronym at the moment, but it basically states that if you're found in possession of anything encrypted and you can't or won't divulge the key or other means of decrypting it, that they can jail you for up to 5 years (IIRC) and pound with some massive cash fine.

So, basically - using web proxies for activities like UK420 -

no point really - it doesn't achieve anything other than keeping the IP address that you're currently using from Joolz, ¿and if you don't trust him then what the hell are you doing on here at all?

There are whole communities out there using 'darknets' which are invite-only and are based on 'webs of trust' with file sharing and websites, the lot - it's basically like a (private) mirror of the 'lightside' of the Internet.
¿As a matter of interest,
Booj - ¿what 'darkness' have you been witness to in the
e2a: I remember what the law is - it's
The Regulation of Investigatory Powers Act 2000 (RIPA)