This announcement by Mastercard is very 'interestingly' timed! It will also be interesting to see how they think this won't lead to increasing prices. 

For now, merchants should be checking their contracts with their payment processors to see whether and how these costs may be passed on to them. Many contracts will have 'Interchange plus' based charges - meaning that the fee which the merchant pays the processor for each card transaction will be based on the relevant Interchange fee 'plus' the processor's margin. If this applies then the cost to a UK merchant to take EU card payments will increase. That cost has to go somewhere...