Extract From the U.K. government website.
If you need emergency medical assistance during your trip, dial 112 and ask for an ambulance.
You should get a free UK Global Health Insurance Card (GHIC) or European Health Insurance Card (EHIC) before leaving the UK. If you already have an EHIC it will still be valid as long as it remains in date.
The GHIC or EHIC entitles you to state provided medical treatment that may become necessary during your trip. Any treatment provided is on the same terms as Spanish nationals. If you don’t have your EHIC with you or you’ve lost it, you can call the NHS Overseas Healthcare Team on +44 191 218 1999to get a Provisional Replacement Certificate.
It’s important to take out appropriate travel insurance for your needs. A GHIC or EHIC is not an alternative to travel insurance and you should have both before you travel. It does not cover all health-related costs, for example, medical repatriation, ongoing medical treatment and non-urgent treatment. Read more about what your travel insurance should cover.
As a general rule, if you need hospital treatment in Spain you’re more likely to receive appropriate care in a public healthcare facility (although in some tourist areas there may be no public healthcare facility nearby). Your insurance/medical assistance company will be able to provide further details. Some hotels may call private doctors or ambulances to take patients to private hospitals; the EHIC won’t be accepted there. For more information visit Healthcare in Spain.”