Is Great Britain is becoming a police state?

I just came across this Youtube clip. There are plenty of aspects of this which are alarming, but I think probably the most alarming is the fact that the police were so unprofessional in their conduct. It isn't the job of the police to stop people from doing things which are perfectly legal. When they start using anti terrorist legislation against people who are quite clearly not terrorists, we have problems.  Hat tip to Dr Rachel Joyce for the clip