That's pretty weird... http://mashable.com/2014/10/30/cops-can-force-you-to-unlock-phone-with-fingerprint-ruling/
The UK already does require handover of your encryption keys and presumably your account passwords too.
For some reason this doesn't surprise me at all. I wish it did!! Similarly, this is why I use strong passwords on my data encryption vs a "token" which would be much easier due to repetitive usage.