The NHS is a "divisive influence" which favours the assertive middle classes over poorer people, a study says.
More private sector involvement is needed, Civitas says
The report by centre-right think-tank Civitas said the health service was not providing equal treatment to all.
It pointed out that people in deprived areas were often more in need of treatment, but less likely to get hip replacements or key x-rays.
The report called for more use of the private sector, but other experts said this would just widen inequalities.
Report author Nick Seddon said studies had shown that those on lower incomes made more use of primary care, but were less likely to be referred on for hospital treatment.
He highlighted York University research which showed those in deprived areas were more likely to need hip replacements but less likely to get them.
And the report also mentioned another study which found angiograhy - x-rays of arteries and veins - rates among the lowest socio-economic groups were 30% lower that in the highest.
Mr Seddon said this was partly attributable to the fact that middle classes were more assertive, articulate and confident in dealing with health professionals.
"Much depends on where you live, how much you earn, how old you are and crucially who you know.
"It has always been said in defence of the NHS that, although it was not the best in terms of quality, it was at least impressive in term of equity. Now that is no longer true.
"The NHS cannot be allowed to continue as it is."
He said part of the problem for the NHS was that it had made little use of the private sector.
He suggested the NHS could learn from other European countries with social insurance schemes which encouraged companies to get more involved in health.
"In the NHS, private providers have only really got involved in non-emergency operations to date, but why can't they do more? What about heart and cancer care and GPs?
"By introducing the private sector, you increase competition and drive up standards."
But Alex Nunns, of the Keep Our NHS Public campaign group, which represents health professionals, the public and academics, said: "The middle classes will always make the best of a system.
"In fact, there is evidence to show that when you involve the private sector, it just exacerbates the situation."