The National Health Service should be an independent public corporation with its own constitution similar to the BBC and the Bank of England, a report says today.

Existing measures for securing accountability in the £54bn service, Europe's largest employer, are "unacceptably weak", says the report by the Commission on the NHS.

The group, chaired by Will Hutton, chief executive of the Industrial Society and a former newspaper editor, was established a year ago by the Association of Community Health Councils to examine how the public interest was being served by the NHS.

The report says although the NHS enjoys unrivalled public support, it is a closed, defensive, inward-looking institution that needs to be open to public scrutiny to improve standards and increase public involvement.

A poll for the commission found 63 per cent of people named the NHS as "the most valuable institution for this country" but almost the same proportion (62 per cent) said it needed to improve "a great deal" or "quite a lot".

The next most valuable institution - Parliament - attracted only 12 per cent of the votes, with the BBC getting 4 per cent and the Royal Family 3 per cent.

Two-thirds of respondents (67 per cent) agreed that the NHS needed a constitution to define "the Government's duty to deliver free medical care at a time when people need it".

The report says the NHS is one of the least accountable of Britain's major public institutions and establishing it as an independent body with a constitution would render its decision-making more transparent.

The new NHS would carry out government policies within the resources allocated, but deciding policies, allocating and using resources and delivering care and services would be made transparent instead of being contained within the "opaque processes of a government department".

Mr Hutton, author of The State We're In , the best-selling economic and political analysis of the state of Britain, said: "We are challenging the notion of Alan Milburn [Secretary of State for Health] being chief executive of the NHS.

"The existing systems for maintaining accountability are weak. That leads to a producer-oriented culture that is defensive, inward-looking and blaming."

Government plans to increase central control over the NHS are likely to weaken accountability further, the report says. There is no settled system for delegating decision-making to regional and local levels, and although there are ad hoc inquiries, reviews and a complaints system for individuals, none are backed by a constitutionally entrenched framework of patient rights.

The report says: "Equality of access to health will be legally binding. The need to ensure equality of treatment regardless of age, gender or race would be a constitutional requirement. The gross inequalities of postcode prescribing and the worst results of PFI [private finance initiative] contracts would be constitutionally forbidden. Complaints procedures can be vastly strengthened and constitutionally entrenched."