I must be one of the minority when I say I do not use a mobile phone. I do have one but it stays mostly in its box. I hate this habbit of taking your 'phone to the dinner table. First of all it is bad manners, but I can think of nothing more rude than saying 'sorry I have to take this' when you are with others eating a meal. You DO NOT have to take the 'phone call, in fact you should not have your 'phone switched on when you are with others. To me this is like saying 'Sorry, you are so boring I will talk to whoever is calling me because they are more interesting' OK it may be an emergency, but that is different. If something is likely to happen then leave the 'phone switched on, but for everything else you should ignore the call.
When I am on a bus or train I do not want to hear people's conversations on their mobiles either. Keep them in your pocket.
Also these 'phones are putting little children at risk. How often do you see mothers wandering down the street with 'phone stuck to her ear, while little one is walking behind, out of sight, out of mind, she cannot see what he/she is up to and they could actually decide to cross the road to see something and mother would be no wiser. Not to mention how often children simply go missing these days. It takes just seconds for them to be snatched and driven away.
To think that London, or anywhere else for that matter, does not belong to any one demographic