The service is a source of love, pride and frustration in equal measure, but woe betide anyone who is perceived as a threat to it.
Before the rebranding of the Conservatives under David Cameron, the party was seen as the enemy of a state health service, just as its reputation was as the enemy of any 'old-fashioned' nationalised service.
But once this change had taken place, a new message began to resonate with voters - that the Conservatives were not 'anti-NHS'.
In a time of pragmatism about national finances, economic stagnation and enough other bad news stories to make one consider relocating to Azerbaijan (I gather the music's fantastic), the need to reform the NHS is a message that could have achieved traction. It would run along the lines of: 'We've got less money to spend, we're living longer and we want to ensure that the NHS is as efficient as possible to maximise the amount that goes directly to patient care.'
So what's gone wrong? First, the Government seems to have forgotten how well-loved this old relative is and assumed that people will buy into change as a matter of course. They won't.
The case was not made effectively from the outset. The preparation was wrong. The messaging was unclear. The third parties (the British Medical Association for one) opposing it are startling in their number and their rigid stance.
To cap it all, the coalition's minor partner is conflating NHS reform with the Government's future. The changes have yet to be sold to the Lib Dems and after their beasting at the polls last month, the job has become that bit more difficult.
"The need for NHS reform is a message that could have achieved traction. So what's gone wrong?"