Martin Ryan had been admitted to hospital after suffering a stroke
A health watchdog should issue damning verdicts on six deaths of vulnerable NHS patients, a charity has said.
The Parliamentary and Health Service Ombudsman is due to rule on the cases highlighted by Mencap later this month.
They include Martin Ryan, 43, who spent 26 days without food before he died, after staff did not fit a feeding tube.
Last year an independent inquiry into the deaths said laws to protect people with learning disabilities were being ignored by the NHS in England.
Mr Ryan had been admitted to hospital after suffering a stroke which made it difficult for him to swallow.
Other cases included Emma Kemp, of Newbury, Berkshire, who was not treated immediately for cancer because doctors said her communication difficulties meant she was unable to consent.
The father of Mark Cannon, 30, said hospital staff had failed to give his son replacement epilepsy medication during an operation after he was admitted to hospital with a broken leg.
Mencap highlighted the cases and three other deaths in a report called Death By Indifference which was published in March 2007.
'Irrational and perverse'
The charity's chief executive Mark Goldring told the Daily Mail: "The ombudsman's reports must condemn the appalling failings of the NHS in these six cases.
"They need to make it impossible for people with a learning disability to continue to die unnecessarily.
"A failure to do this would be irrational and perverse.
"The reports have a duty to challenge complacency where it has been shown to exist in the health service when treating people with a learning disability and must hold individuals to account for their actions."
Mr Goldring said Mencap had "fought and will continue to fight for justice for their families".
The ombudsman declined to comment ahead of the publication of its report.