Booked for using mobile while stationery

A question about : Booked for using mobile while stationery

I have a friend who came out of a building and got into his car, which was parked on a main road. He started the car first to warm it up (diesel car) and texted his office that he was on his way. Suddenly he was approached by a West Yorkshire Police officer and booked for 'using a mobile whilst driving'.
He had his handbrake on and had not put car in gear; only engine was running to allow car to warm up. Its a bit harsh to get booked for that?
I guess its never safe to use a mobile in a car; only way is to switch car off and go outside.

Best answers:

• Engine was running, people should know the rules of the road if they're going to drive
  (diesels don't warm up idling)
  Is a bit harsh, but is the way it is.
• Aye shoddy law enforcedunfairly and disproportionately.
  He knows now though. Not really doing the polices rep any good giving out tickets like this either.
• They are relying on him just paying up.
  If the car was parked it was not been "driven"
• The more idiots like your 'mate', the less the rest of us have to pay.
  Well done to your 'mate'!
• Using mobile phones when driving: the law
  Quote:
• What are you two tittering on about ?
  Go do it via PM