Using plastic overseas? Always PAY IN EUROS (even if it says 0% commission)

Update 3 May 2022: I wrote this blog back in 2013, but while it's a little dated, and the rates are wrong, the logic is still the same.

I couldn't believe my ears. While filming in southern Spain for the new series of my show, the producer told me he'd found a cash machine offering 0% commission if you chose to withdraw in pounds. In theory, that'd mean PERFECT exchange rates.