EU citizens and the NHS - remember I am only looking at EU nationals and not Health Tourists as a whole.
Information from the Kings Fund and NHS site
Some services are free of charge to anyone they are GP AND A&E, and of course various infectious diseases.
Other access depends on immigration status.
Immigrants from the EU qualify if they have ordinary resident status (see above) so use of the NHS is not (as I once thought) dependent on nationality, payment of taxes, NI contributions, etc.
Those who don't yet have this status can still have free treatment only if there is a reciprocal arrangement with their country of origin, and by using the EHIC issued by that country. Just as we do when we go on holiday (I had to use it once in France when I crushed some vertebra in my back and very impressed I was too - especially when I was taken to hospital by some big burly firemen - they seem to double up as ambulance people?)
Now with regard to the statistics of the cost, I have spent a lot of time trying to find this however I eventually found this on the Kings Fund
There is a large degree of debate around this area, but there is a total lack of reliable data on the use of the NHS by immigrants and visitors.
So don't believe anyone who says different!!!! That's my bit.