NHS trusts and their lawyers should be forced by law to reveal when care providers have made serious mistakes, campaigners have said in the run-up to the report of the inquiry into alleged failings at Mid Staffordshire NHS Foundation Trust.

Peter Walsh, chief executive of patients’ charity Action Against Medical Accidents, said the government must improve the way NHS managers deal with complaints.

The report, following an inquiry chaired by Robert Francis QC, is expected to recommend a statutory ‘duty of candour’ requiring healthcare organisations to be open with patients or their families about lapses which cause harm.

Walsh said he fears that the health secretary, Jeremy Hunt, will ignore the recommendation in favour of a ‘watered-down’ approach that would relegate the issue to a contractual matter.

He rejected the idea of a ‘default denial position’ taken by all NHS trusts but said failure to give full disclosure was more common than people may think.

‘A duty of candour would mean a complaint is dealt with up-front,’ said Walsh. ‘It has got to be more pro-active as an economy with the truth is the most common thing we see – [trusts] let the patient bark up the wrong tree rather than tell them what went wrong.

‘They should be legally bound to tell all. If you’re the kind of organisation prepared to sweep such things under the carpet you’re precisely the kind of organisation that will turn into another Stafford.’

The Francis inquiry is expected to refer to the aftermath of the death of John Moore-Robinson in 2006, when the family and coroner were not told about the existence of an internal report identifying alleged failings in his care.

Walsh said the legal team in that case should have had a duty to pass information to the relatives of the deceased man rather than just protect the interests of the hospital.

The report, to be published on Wednesday, may also include recommendations over minimum staffing levels and support and protection for whistleblowers.

Walsh has written to the health secretary warning that a failure to implement the recommendations in full ‘would not only be a massive waste of public money and wasted opportunity, but would be a betrayal of patients and the NHS’.