A watchdog has expressed astonishment at the failure to introduce a "properly resourced" national strategy for older prisoners after a dramatic rise in inmates aged over 60.
Nigel Newcomen, the Prisons and Probation Ombudsman, said staff are managing ageing prisoners with limited resources and inadequate training.
He warned his office finds too many cases where terminally ill inmates are being "unnecessarily and inhumanely" shackled.
In one case cited in a review by the ombudsman, a prisoner was still chained to an escort officer at the time of his death in hospital.
The population behind bars in England and Wales has been ageing in recent years, driven largely by increased sentence length and more late-in-life prosecutions for historic sex offences.
The number of prisoners aged over 60 has tripled in 15 years and projections suggest the trend will be even more marked by 2020.
Mr Newcomen found there has been "little strategic grip" of the sharp demographic change, with prisons and healthcare partners left to respond in a piecemeal fashion.
"The inevitable result, illustrated in my review, is variable end of life care for prisoners and a continued inability of many prisons to adjust their security arrangements appropriately to the needs of the seriously ill," he said.
"I still find too many cases of prisons shackling the terminally ill - even to the point of death."
Mr Newcomen said he had seen examples of "impressively humane" care for the dying by individual staff, as well as glimpses of improved social care and the development of some "excellent" palliative care.
But he added: "I remain astonished that there is still no properly resourced older prisoner strategy.
"This is something I have called for repeatedly and without which I fear my office will simply continue to expose unacceptable examples of poor care."
The ombudsman's report identified lessons from 314 investigations over 2013-2015 into naturally caused deaths of prisoners over 50.
Recommendations include: prisons should ensure that newly arrived prisoners have an appropriate health screen that reviews their medical history and conditions; use of restraints should be proportionate to the actual risk posed by the prisoner; and prisons should ensure that terminally ill prisoners who require intensive palliative care are treated in a suitable environment.
A Ministry of Justice spokesman said: "We are grateful to the Prisons and Probation Ombudsman for the work they have done in compiling this report and we recognise that there has been an increase in the number of prisoners from this age group.
"We have guidance in place for the management of older prisoners and we are committed to ensuring all prisoners are treated fairly and with dignity. We will continue to keep the treatment of older prisoners under review.
"Additionally, we work with NHS England to provide the appropriate care and treatment for this group of offenders and a number of prisons make specific provisions through dedicated wings and units, adapting their regimes according to need."
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