|European Health Insurance Card.|
The Reciprocal health agreements with EU countries and others allow for your medical expenses to be paid for (Or Partly paid for) by the government of the country you are visiting with an ultimate claim back to the UK Government, eg Free medical care. It is as if you were resident in the country and you will receive the medical care that any citizen would receive, pobiously some countries care systems are not as good as the UK's but some are better!
But you have to apply for a EHIC card Government official Link , be careful that you go to carpetbagger sites that charge you this is free, so use that link,
If you want to play it 100% safe then can I suggest getting a quote from here Insurance Link its particularly good for under 55's, but can do 55-65yrs as well, but I would still apply for the EHIC.