As every consumer and business traveller in the European Union knows, spending money abroad is not as simple as it looks. Payment cards that are widely used in one country are not accepted in others. Transaction costs are high and cross-border money transfers take a long time to process.

This means shoppers are often forced to use cash abroad, a simpler but also less efficient way of paying. And Europeans who have to make regular cross-border transfers – for example because they own a holiday home in another country – almost always open a bank account in the country where the bills fall due.