[eigenvector]

You can be jailed for a tweet pretty much anywhere if that tweet is a direct, credible threat of violence.

[krylonkid]

In the UK you do jail time if it hurts someone's feelings.

[sanityinc]

The law responsible for that was recently overturned: http://reformsection5.org.uk/

In short, it is no longer illegal to use what a policeman or court might judge to be "insulting words or behaviour".