Which is the best network on the 'Pay as you go' tariff, which would be mostly used for mobile-to-mobile calling? All answers would be greatly appreciated.
I'd go with rja's advice, but if the mobiles you are calling are all on different networks, take a look at Virgin. I got a mobile a couple of months ago and after comparing all the prices - which is very confusing - it seemed that Virgin offered the best deal by far.