Evidence is growing that in some EU member states the European Health Insurance Card is being refused by rogue hospitals.
Last month the Independent on Sunday reported on how British holidaymakers in Spain were being presented with bills for hospital appointments and surgical procedures despite having a valid and up-to-date EHIC.
Now one of the UK's biggest travel insurers Columbus has issued a stark warning to holidaymakers.
Greg Lawson, the head of retail at Columbus Direct said: "A number of Columbus customers have experienced issues trying to use their EHIC card in Spain and other EU countries, although our emergency assistance team have then stepped in to manage the situation. Where we cannot recover these costs… these increased costs will then unfortunately be passed to consumers in increased premiums."
Meanwhile, research from Asda money has shown that a large proportion of Britons routinely overestimate what the EHIC covers them for.
A third of parents think it covers all insurance needs when in Europe it only provides medical care at the same cost as a national of that country, meaning they could still be left with a huge bill.