Maybe they'll decide that your ethnic heritage means you need to be segregated. Maybe they'll decide that since you're university-educated you need to be killed. Who knows? And even if you're as vanilla as they come, you should be equally concerned about what that means to the rest of the citizenry. Also, you may not be political now, but what about when they start cracking down on something you would be political about? Would you have second thoughts about marching in a protest when you considered all those cameras? What does that mean to the state of protest in general?

Look, I don't think that the UK is a bad place to live, nor do I think that the UK government would set up these cameras for the notion of controlling its populace, but once that infrastructure is there, it becomes available for abuse, both above and below board.