A closed-doors inquiry into the “shocking” number of deaths at Stafford Hospital has been criticised before it has been held.

The campaign group Cure the NHS says that the inquiry would not establish what went wrong at the hospital, and that its terms of reference are too narrow.

For instance, it would not examine why problems were not detected earlier at the hospital, where up to 1,200 more people died than would have been expected between 2005 to 2008.

The Healthcare Commission has already published a damning report detailed a catalogue of failings at Mid Staffordshire trust, which runs Stafford and Cannock Chase hospitals.

Appalling standards of care for patients put many people at risk and between 400 and 1,200 more people died than would have been expected in a three-year period from 2005 to 2008, the commission found.

But Mr Francis said the inquiry would not be a forum for debate about the role of regulators and other statutory bodies in the events at Stafford between 2005 and March 2009.

During a meeting with the campaigners and relatives, Mr Francis said the Health Secretary had made it clear that the inquiry should deliver key lessons.

The QC, a specialist in medical legal issues, said: “The lessons to be learned from these stories - and I am already confident that there are such lessons - will be reported so that they can be taken on board by the new management of the trust.