I thought the post about passwords being covered by fifth amendment rights in the US was really interesting so I've done some research about the laws in the UK, and unfortunately these laws do not apply.
In the UK you can be jailed for refusing to give up your password for an electronic device or drive. It's not quite the land of the free here.
David cameron is trying to make encryption illegal. (Not PGP I don't think, modern encryption they haven't had 25 years to weaken and de-randomize)
After that, its going to be illegal to whisper, in case you're whispering about terrorist acts.
You'll need a Home Office licence for venetian blinds and its curtains for curtains.