Individual trusts and/or sections of trusts would be sold off to private healthcare companies.
I don't know the legal ins and outs but any part of the NHS could feasibly be sold in theory. So if your local hospital trust is contracted out and you need emergency treatment, they fix you, then send the bill. It would take a while to get to that point admittedly but it's nearly on the first step of that slippery slope.
I'm not talking about social care, which is private.
It is complicated and sounds weird but it's also not a good thing if it comes to pass, which I hope it won't.
But a private company wont buy it if it cannot turn a profit. And folk who want to pay for private in the UK are already taken care of, so to speak.
Like, about 10 years ago, I had the snip. Spoke to my GP, just a phone call cos I knew her well. Non emergency, obviously, and the NHS waiting list was 6 months. (Fair enough, its kind of a life style thing). Called Bupa, £180, all in. Sorted a few days later.
Point is, when I had a few bob, I was happy to pay a relatively modest amount, as a private citizen, for non essential health care.
So I am starting to get the feeling that there are some scare mongerers, (not you mate), who lob the "Tories will sell the NHS" stories about, without really thinking it through.