On friday 25/08/06 I attended the monthly critical mass,as usual it was a good turnout and a geneial crowd. I had noticed that there were many more police cyclists than I had seen on the last two rides. As we were cycling down the Mall I witnessed a police cyclist deliberatly bumping into cyclists,I pointed out to the officer that his actions were unjust and illegal,I then asked him for his number which he gave as D360,he then asked me if I was going to complain against him. I cycled away from him.When the ride stopped briefly at Trafalgar Sq the same officer stopped near me and a friend staring intently at us.A collegue joined him and they engaged in name calling,D360 then unclipped his CS gas cannister,I took this to be a threat,I took out my mobile phone and began to film his actions,at this he and his collegue moved away. Towards the last stages of the ride the police became increasingly aggressive by bumping into cyclists,bumping peoples back wheels.On more than one occasion I witnessed police cyclists mounting the pavement(surely an infringement??).On several occasions they just barged past people,I felt compelled to point out that by using the words "excuse me please" not only would people know that they were required to move,in a civilised society manners go a long way in keeping people genial and non confrontational. If the police are to insist on joining the ride surely it`s not too much to ask that they act professionally,after all as I pointed out to one irate policeman,they are public servants,we are the public. It seems to me that thier presence is there to be confrontational rather than to police a situation.It has been mentioned that legal observers are being considered.I think this to be a good idea,after all,who polices the police??