A family member recently picked up a ticket for driving through a red traffic light (not on his phone, just not concentrating sufficiently - fortunately it was at dark o'clock & no accident occurred). These days, you can either take a £60 fine + 3 points on your licence, or go on a 1 day road safety course (cost: £60) and they will waive the points. He opted for the course.
According to the guy running it, one of the biggest problems with a large and growing proportion of young drivers is their absolute inability to not respond to the phone - especially texts - absolutely immediately. This is, as you might expect, causing a road safety nightmare...
In theory, using a mobile phone whilst you're driving is illegal in the UK. Hands-free systems fall through the net (not because they're exempt, but because the police can't tell that you're using one). In practice, I see more & more people with phones stuck to their ears whilst driving; and you can always tell someone who's using their phone: They drive exactly the same as someone who is drunk.