Quote from the Crown Prosecution Service's website:
"The following are examples of driving which may amount to driving without due care and attention:
* using a hand held mobile telephone while the vehicle is moving;
* tuning a car radio;
* reading a newspaper/map;
* selecting and lighting a cigarette/cigar/pipe;
* talking to and looking at a passenger"
http://www.cps.gov.uk/legal/section9/chapter_b .html#21
So, it's already recognized (by those responsible for law enforcement) that such actions can be dangerous and irresponsible. There are clearly some 'grey areas' where, say 'tuning a car radio' is concerned. However, there is plenty of research to show that using a hand-held phone considerably increases the chance of an accident, so it seems logical to create a 'black and white' definition of illegality for such actions.
My only concern is that the penalties are nowhere near stringent enough. I would suggest a fine of �1000 and a 6 month ban.
Chris