The NHS has survived for 60 years without a constitution; this week it will be told it is to have one that sets out the rights and responsibilities of patients and staff.

Lord Darzi of Denham has had the tricky task of drafting a document that is neither too detailed nor too vacuous. Too many promises that cannot be met would provide joy to lawyers but to nobody else. Too few, and the constitution is likely to be derided as a restatement of the obvious.

Those who pay for the NHS through their taxes have a right to medical care, but no right to demand particular types of care. The constitution will not change that. Any system of healthcare has to draw the line somewhere, and the National Institute for Health and Clinical Excellence (NICE) will provide the evidence on which to base rationing.

In the Darzi constitution, patients may be given the right to be treated within a certain time and the right to choose where they are treated. There is an irony in the second of these, because one of the first acts when Labour was elected in 1997 was to restrict choice.

Patients will be promised that they will be treated with dignity and respect, and staff that they will be valued and respected. The core principles of the NHS – a universal and comprehensive service with equal access for all, free at the point of use, and based on clinical need, not ability to pay – will be restated.

Given its title, an NHS constitution will need to be enforceable legally if it is to avoid being as quickly forgotten as the Patient’s Charter of the Nineties. Any written constitution requires a court to enforce it – one reason why Britain has no constitution, preferring the judgment of Parliament to that of judges.

Another requirement generally expected of a constitution is that it shall be hard to change, calling for a two-thirds majority of those voting. But Parliament can change any law it fancies on a simple majority. How Darzi hopes to square this particular circle is anybody’s guess.

Logic would suggest that an NHS constitution worthy of the name would require cross-party support to enact or to change. Is this really a sensible way to run what is, behind all the pieties, only a vehicle for providing healthcare?

These dilemmas make it likely that the NHS constitution will be that only in name. In practice it will amount to a restatement of the aims of the NHS Plan of 2000, with a few add-ons that have emerged since then, such as Patient Choice. It will apply only to England. Scotland, Wales and Northern Ireland have gone their own way and run their own versions of the NHS.

It’s a lot of effort for little discernible reward. But logic has never held much sway in an organisation that for some has acquired quasi-religious status.

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