@Gordon
"Its should be expected that the police try to push the boundaries - infact its healthly that they do so."
No way in hell is it "healthy" that the Police push the boundaries, see the G20 protests (aggressive tactics, concealed ID numbers, assaults etc) for what happens when those boundaries start getting pushed!
The job of the Police is to Maintain the Queen's Peace so that people may go about their lawful business without let or hindrance and investigate breaches of the law, however they *MUST* do it within set limits otherwise they start becoming "Judge, Jury and Executioner".
Remember that the Police are a civilian organisation subject to the same laws as the rest of us.