Sad to see that all the replies to the thread title agree on my observation of the prevelance of mobile phone usage by motorist. I think we at least need a government campaign reminding drivers of the potentially fatal consequences and of the penalties if caught should they ever see a policeman.
Unfortunately,, it is so widespread that it has become normalised behaviour for a lot of drivers now.
For example, recently during my early morning commute along country roads I encountered a driver of an American style pick up truck who was weaving all over the road often veering towards oncoming traffic. I was careful to select the right moment to overtake him and as I did I could clearly see he was head down texting so I shouted get off your phone. He was incandescent with anger and did all the usual stuff of driving to close behind me and then overtook me and tried a brake test. The episode finished when he sped of, pulled into a lay-by and was out of the car beckoning me to pull over so we could come to blows - needless to say I didn’t stop and continued on my journey.