Hi Lance,
unfortunately, unless you set up to use "international roaming" before you leave Turkey, you will not be able to use it here. Are you on Turkcell? If so it may be worth your while to set up an on line account next time you are over and you will then have the option of logging on from the uk and even topping up your phone (as long as you remember to buy some credits to bring back home with you.)
Not sure about other networks.