New guidelines now mean that drivers using mobiles, sat-navs or MP3 players whilst driving could be considered to be driving dangerously instead of carelessly and may face up to two years in prison, instead of just a fine, disqualification or community order.  The most severe death by dangerous driving cases may also be prosecuted as manslaughter cases.  This does not mean that everyone driving whilst using a mobile etc will go to prison, just those involved in accidents or incidents where danger has been caused by their actions.
See Times - 20/12/07