The junior health minister Ara Darzi proposed it. The prime minister endorsed it. The BMA supported it. The secretary of state for health is busy working on it. The notion that the NHS should celebrate its approaching 60th anniversary by unveiling a constitution now has a seemingly irresistible momentum. Who can argue against an NHS constitution that would, in Lord Darzi’s words, “enshrine the values of the NHS,” “increase local accountability to patients and public,” and “define the rights and responsibilities of patients?”

The rhetoric is seductive. But once we start thinking about how we might translate it into practice, the arguments begin. Let’s start with the rights and responsibilities of patients. How are these to be defined? Will the rights be restatements of existing policies about waiting times between referral and treatment or in accident and emergency departments? Or will they define entitlements to a specific package …