I think the NHS is well known. So no explanation needed. God bless the NHS.
Now what I do want to talk about, is the Dutch public health system, which I am in now. Everyone is required by law to get insurance. Health insurance here is mostly private however. If you can't pay those, the government appoints you one. It isn't much. You can choose to leave out certain things to make it cheaper, like alternative medicine, which for some strange reason is also covered. There is basic insurance that is practically the same for everyone.
As for the quality itself. It is great. I had my tonsils removed (Most painful week of my life). The hospital stay was excellent. I also broke my hand last year. The emergency waiting times were awful, but the treatment was again, excellent.
