Phones UK StyleMobile (cell) phones in the UK all have a different prefix than land line numbers and cost more to call to. All mobile start with 077, 078, or 079, while most London land line numbers start off 020 and as you get outside of London you will find 018, 013, etc.
In the US you can't tell a mobile from a land line number at all & costs are the same . . . which I must say I like much better, though it is kinda nice to know if you're calling some one's house for mobile, but I'm not a fan of the price difference over here!