> Using RIPA 2000 they can still put you in prison for up to 2 years for refusing to give up your encryption key.

2 years for non terrorism related cases. 5 years for anything "national security" related.

e.g. model plane enthusiast with mental health issues? http://www.theregister.co.uk/2009/11/24/ripa_jfl/ worth reading the whole thing as it does a lot of analysis and gives lots of detail.