Jane is quite right, and having members of my family at present serving in the police force, I can tell you, they do not look forward to these encounters at all. sometimes they themselves agree with the protest, sometimes they don't, but it's their unenviable job to keep the peace at them and not allow it to develop into a full blown riot.When you think how few in number they are compared to the demonstrators, you will understand that under their 'poker faces' they are often very scared.The Ian Tomlinson case was different, there were few people around when the officer assaulted him, and the demo was over.The officer in question was already viewed with suspicion by his own fellow officers and superiors for other dubious actions, and that was the last straw.