Professor Steve Field told GP that the document, published this week, made a 'very strong statement about the role of the GP as the main point of access to NHS care'.
Early drafts barely mentioned GPs, and language which says that patients have a responsibility to register with a practice was only added after 'quite a bit of debate', he said.
But its inclusion 'will reinforce the role of list-based GP services at the NHS's heart', he said.
The NHS constitution outlines the rights and responsibilities of the NHS, its patients and staff. It includes the right of patients to choose their GP practice, and to see a named doctor.
The constitution was part of the Health Bill - read in parliament for the first time last week - which will make many of Lord Darzi's reforms law.
Other measures include patient budget pilots, and a demand for NHS providers to publish annual 'quality accounts'.
GPC chairman Dr Laurence Buckman said quality accounts had not been discussed with the GPC. 'I don't think they're in my terms of service,' he said.
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