> Good luck finding out ahead of time whether your foreign card is going to be accepted by the system.
On the tills themselves there's all the signs of all the accepted cards and it was a fairly exhaustive list. It's also probably available online, so it should be pretty easy to check ahead of time.
"Many contactless cards issued outside the UK can be used to pay as you go for travel (overseas transaction fees may apply):
American Express (AMEX)
MasterCard and Maestro (some cards issued in the USA, Canada and the Netherlands aren't accepted)
Visa and V PAY (some cards issued outside the UK aren't accepted)"