The Archbishop of York has warned of the dangers of introducing a more commercial culture into the health service, saying "you cannot compare an NHS hospital to a supermarket".
Dr John Sentamu spoke out following recent surgery to remove his appendix after he was taken ill in London.
Writing in the Yorkshire Post, he said: "We must never allow health provision in this country to become exclusive. Decent healthcare should not solely be the preserve of those that can afford to purchase it. I am certainly not persuaded by internal competitive markets when one is treating very ill patients."
The archbishop said: "We need to recognise that there are no easy answers when we look at the demands on the NHS. Whilst we may strive to deliver value for money, we cannot allow care to be market-led or commercialised to the point where patient safety is put at risk. You cannot compare an NHS hospital to a supermarket."
Dr Sentamu said society had "perpetuated the myth" that the private sector works better than the public sector and this does a disservice to devoted public sector workers.
And the Archbishop said he was also concerned that inequalities in health outcomes continue, despite strategies to spread finance for health care more fairly. But he said health care problems cannot be solved by simply "throwing money" at the system.
He called for a national debate on health care provision. "As our political leaders embark on reforming the NHS via the Health and Social Care Bill, I would like to see a national debate take place - one that would re-examine the relationship between the individual, society and the state - and not be afraid to question our own expectations of health care provision," the archbishop said.
"We all want to see a system that is compassionate and responsive. We all want to see investment spent appropriately to provide the best care possible to as many people as possible. The challenge is how do we achieve that. Let us aim high as we set out upon this journey - and let us aim together."
Dr Sentamu was taken ill when he was in London in May to listen to US President Barack Obama address the Joint Houses of Parliament and attend a Service of Thanksgiving for Lord Bingham. He was treated at St Thomas's Hospital.
A Department of Health spokesman said: "We welcome the Archbishop Sentamu's comments. Our Bill puts clear safeguards in place against any abuse from the private sector and ensures that all provision of services to NHS patients will be based on the quality of the service to patients, not the cost."