PO's Mobile Phones

Dear Deputy Mayor,

As a result of discussions with a number of friends and relatives I am doing some personal research into the use of hand held Police Radios whilst the officer is driving a motor vehicle on a public road. If a member of the public is seen using a mobile phone whilst driving a motor vehicle on a public road they can be prosecuted and the sanctions can have serious implications. If they are involved in an accident the police can make lawful enquiries to ascertain if the driver was using a mobile phone at the time, which can make any offence more serious and aggravated. In London, police officers are often seen, in uniform, driving police vehicles whilst operating and speaking into hand held radios which are attached to their epaulette or the front of their uniform. This requires them to steer and drive with one hand. We cannot see the difference between this and the use of a mobile phone whilst driving. I would be extremely grateful if you could explain and answer the following - 

                         Are Police Officer exempt from the laws relating to the use of such devices whilst driving ?

                         If an police vehicle is involved in a road traffic accident do the investigators check to ascertain if the driver was using a mobile phone or hand held radio?

                         Is there a "handsfree" option installed in police vehicles?

                         If there is a "handsfree" option why are officers not using it?

                         How many officers have been disciplined or prosecuted for driving whilst using such devices.  

I hope you will be able to answer my queries. Thank you for your assistance in these matters.