As of May 2009 Nationwide will be passing on the transaction fee imposed by Visa on overseas credit card transactions and, as of June 2009, the same will apply for debit cards.
Quote:
When you use a Nationwide Visa debit card or credit card to make a transaction in certain currencies other than sterling, Visa charge a fee for each transaction and Nationwide currently pays that fee on your behalf.
We will start to pass this fee onto you from 6 May 2009 on credit card and from 1 June 2009 on debit card and it will be included in the sterling amount shown on your statement.
The fee is currently 0.84%. From 1 July 2009 this fee will increase to 1%.
The list below provides details of the countries for which Visa charge a fee. To check if you will be charged, please search for the country you are visiting by using the A-Z list. Unless stated otherwise a fee will be charged.
Looks like Turkey will be free:D
Taken from Nationwide web-site.