It seems, judging by the lack of response, that many are as perplexed as you. I am surprised that one particular individual has not held forth on this topic.
It is my understanding that at the moment, private companies provide NHS treatment. This was initially to combat long waiting lists and presumably the PCT bought specific services on an as-required basis. So the NHS controlled when private facilities should be used. This is altogether different from having private companies able to compete for providing treatments on a cost basis. Assuming they could undercut NHS services, this could lead to closure af NHS facilities. Once the private comany has a local monopoly, charges would be uncontrollable (look at privatised utilities, who are supposed to compete but follow like sheep when one company raises prices). Presumably he is now saying that this will not be permitted.
Anyway, this is how I see it. I suspect that Cameron doesn't understand what he's talking about. He has been operating in a hands-off chairman position and allowed ministers to develope policies in isolation, nearly all of which have had to have been reversed. He is now trying to play catch-up. He is struggling with policies which are vehemently supportd by the hard-core right and which he has been advised will result in an electoral backlash.