Just for the fun of stirring the pot ... despite the government's protestations, I believe singing "Happy Birthday" may be illegal without a licence. My reasoning is that if people go out to celebrate someone's birthday, they probably intend to sing "Happy Birthday" at some point, so it cannot be spontaneous (even assuming, as Shambles points out, that spontaneous singing is really exempt).

It's not just music this government is out to get, they're planning to outlaw photography in public places and effectively take away your rights over your own photographs:

UK Government nationalises orphan photos and bans non-consensual photography in public