UK mobiles are among the worst in the world in my opinion. I have had top up problems with several UK PAYG Sim cards. Data is often very slow. The worst thing though is the coverage. I haven't found a UK Sim card that works nationally. The coverage maps also lack any detail so you can't plan. Sometimes you just have to go and buy another Sim and top up to make a call.

If you can find a public telephone box it is broken, more often than not, and normally always reaks of urine. Why can't they clean and maintain them?