It was "deplorable" that the patients were left without proper medical cover when health managers discharged them in a ward-closing programme, according to a report into the case which will be published later this week.
The North and Mid-Hampshire Health Authority and the London Community NHS Trust are accused of paying scant regard to guidelines which say that no patient may be discharged from hospital without the authority of the doctor.
The damning criticism is expected to add further fuel to complaints that clinical decisions affecting thousands of pensioners are being overruled by health managers, often for budgetary reasons.
And it will come as the Government considers reaction to its radical proposals for funding care of the elderly. Last Friday was the deadline for responses to its plans which include schemes for insurance against long-term illness and disability.
Four families appealed to the health service Ombudsman, William Reid, two years ago after the North and Mid-Hampshire Health Authority moved 25 dementia patients, most aged over 85, to speed up closure of two long- stay wards at Park Prewett Hospital, Basingstoke.
When doctors initially refused to discharge the five frailest patients, managers brought in an outside consultant who overruled them. Three pensioners, all in the most-at-risk category, died within a fortnight and a total of eight were dead by the time the matter came to public attention. Some did not even have GP cover arranged when they arrived at their new home.
David Chidgey, Liberal Democrat MP for Eastleigh, Hampshire, raised the case in this month's House of Commons debate on dementia. He said there was now clear evidence that health and local authorities were not following their own guidelines on the provision of care.
The authority has since admitted mistakes were made in the discharge process and agreed that it was for the responsible hospital consultant to judge whether or not a patient should be discharged.
It has apologised to Chris Courtenay, who initiated the complaint to the Ombudsman over the death of his 94-year-old father Eddie Ayres.
Dr Pearl Hettiaratchy, one of the overruled consultants, believes it is fundamental to the work of the NHS that medical opinion must prevail.
"If clinicians had been listened to we wouldn't have had all this sadness. We can't say the move caused the deaths but it couldn't have helped," she said.
"When you've been in hospital suffering from dementia, the care team becomes the family of the patient. They are faces in their failing memories."
Dr Hettiaratchy said the ethics committee of the Royal College of Psychiatrists, of which she is a member, would examine the Ombudsman's report.
The report comes as long-term care for the elderly is moving up the political agenda.Reuse content