Would my EHIC card be valid post-Brexit?
For many Brits heading off on European holidays, a European Health Insurance Card - or EHIC - is an essential part of the packing.
The free card entitles travellers to state-provided medical help for any condition or injury that requires urgent treatment, in any other country within the EU, as well as several non-EU countries - Switzerland, Iceland, Norway and Liechtenstein to be precise.
But would the EHIC still be valid if the UK votes to leave the EU?
The short answer - as with many of the issues being debated about the impact of Brexit - is that no-one knows for definite.
EHIC exists within a group known as the European Economic Area, often simply referred to as the single market (plus Switzerland, which confusingly is not a member of the EEA, but has agreed access to the single market).
Therefore, the future of Britons' EHIC cover could depend on whether the UK decided to sever ties with the EEA in the event of a leave vote.
The UK could potentially leave the EU, but remain a member of the EEA, in which case it would keep the existing arrangement.
However, for many Brexit campaigners, particularly those concerned about immigration, there is a drawback to that - the EEA demands the free movement of people, goods, services and capital between member states. And that could be a deal breaker.
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One thing is certain, according to Professor Tamara Hervey, professor of EU law at the University of Sheffield. She says British citizens' EHIC cover will not automatically evaporate on 23 June if there is a vote to leave the EU.
It would remain valid until the date agreed by politicians for the UK to officially withdraw from the EU - at least two years from the vote.
The lead-up time would be spent renegotiating various deals and agreements, which could potentially include renegotiating EHIC cover for British citizens, either with the whole of the EU or with individual countries.
But of course, this is not guaranteed.
"We don't know whether we would be able to renegotiate the terms of the agreement we already have," Prof Hervey told BBC Radio 4's Money Box programme.
"We might be able to do so, but there would be significant uncertainty."
On the other hand, it is worth bearing in mind that the UK has already negotiated reciprocal medical deals with a number of countries, including Australia, under which visitors can receive free urgent treatment. So it could potentially agree similar deals with EU countries.
The Out camp - Vote Leave - argues Switzerland and Iceland are just two examples of countries outside the EU which continue to use this card.
It claims it would be in the EU's interests to continue this arrangement as the UK has given more to other EU countries in medical costs than it has got back, and to suggest otherwise was "scaremongering". The BBC's Reality Check team have analysed that claim.
Meanwhile, the In team - Britain Stronger in Europe - says EHIC allows British families to get "the best possible care without having to worry about the cost".
Health minister Jane Ellison warns there would be no guarantee that British citizens would get access to healthcare while on holiday on the continent if Britain left the EU.
European Health Insurance Card
The European Health Insurance Card, which used to be known as the E111 Card, entitles you to the same state healthcare as a citizen in that country - this includes prescriptions, GP visits and hospital stays.
It covers emergency care as well long term conditions including kidney dialysis treatment.
Care is not always free and the details vary between states depending on their healthcare system. Some costs can be claimed when a patient returns home, but again this depends on the local setup.
The card can be used in any of the 27 EU countries outside the UK as well as Iceland, Liechtenstein, Norway and Switzerland. The Channel Islands, the Isle of Man, Monaco, San Marino and the Vatican do not accept EHIC.
People are still advised to have travel insurance, as private healthcare and flights home are not covered.
Source: NHS Choices