The above person explained it very well, although I feel obliged to point out the pitfalls of going to private companies to provide services versus the NHS providing the services directly:
1. 'creaming off' profitable procedures. For instance, cataract surgery as above is very cheap to perform and is a way for NHS departments to make money because they are paid for their output just like private companies, under the current system. They have to balance the books so cataracts might be a profitable operation for the department and compensate for all of the retinal detachments which may not be profitable (for instance). However overall they break even. Private services tend to offer low risk, quick and cheap operations but they do not have the obligation to provide ALL care. So for instance they could take on all the cataract surgery and make megabucks, whilst the hospital department still has a responsibility for the retinal detachments but now no longer has the financial buffer of the cataracts. They also have a responsibility for the cataract surgery which goes wrong privately. So whilst you're getting great and cheaper services privately, you're actually doing this via sinking the NHS service which now just takes all the non-profitable things like multiple follow-ups, complex cases, high risk cases etc.
2. communication issues... already a problem in the NHS as highlighted in the Francis enquiry, even more of a problem where you're now breaking everything down into multiple companies with their own structures and paperwork. You can't find everything on a central system or wander into the secretaries office to find X person, 'cause it's not there.
3. technically, CCGs are run by people already in the private sector as GPs are private business owners, assuming they're partners, or employed by a private business if they are salaried GPs. So financial decision-making for the NHS has been handed out to people who also are trying to run a profitable business, which is not very helpful. The break-down into CCG structure and the changed role of NICE from regulatory to just 'advisory' also means an inevitable re-introduction of the postcode lottery as different CCGs take decisions as to what to fund or not fund with no real over-arching theme apart from a bit of common sense.
So it's reasons like the above that the 'privatisation', although not true in the sense that the NHS remains non-private on a technical level, is still very controversial and in my opinion (although obviously not everybody's... or at least not Jeremy Hunt's...) seems on paper like a hefty dose of idiocy. Only time will tell whether the ship settles into this new scheme (and actually saves/re-coups any money given how much £££ was wasted firing then re-employing a load of managers and trying to re-structure the system!). I hope it does, but for the above reasons I'm sceptical.