A good comment from a BBC reporter on the 'incident', ''police can use violence but will have to justfiy it''. Having watching the video a number of times, for me the Police officer has done nothing wrong. She marched on him, verbally abusing him, and I can see her push/hit him in the back, and he turns around to defend himself and she got a back hander, he was trying to keep her away from himself, and she was a bit unlucky to get a slap on her face, he could have easily caught on the arm or somewhere else.
It does not matter if she was 2 foot tall, she was inciting the people around, and still continued to advance on him after she got the slap, and so he gave her a whack on the legs, and she backed of then, and more importantly so did the crowd around her. She jumped on a very minor incident which she had nothing to do with, and seemed to be intent on trouble with the police.
She was lucky she was not nicked on the spot. Know doubt if she was, there be a thread slagging the police off for that.