As Hitzi writes in his blog – thanks for the pointer, by the way 
– it is formally possible for authorities in Great Britain to force someone to provide his data in decrypted form or at least provide the passphrase for decryption by the authorities. When I read it for the first time, I thought of TrueCrypt immediately.
This example of Great Britain gives a bitter taste of what’s on the agenda of Western governments after passing all these anti-terror laws already. It hasn’t reached Germany so far, but the fact that there is a precedent, allows others, such as our beloved secretary for propaganda, interior and sports – Dr. Schäuble – to quote the precedent and therefore “justify” their own demands for similar measures 
// Oliver