A man with Down's syndrome who was detained in hospital, then moved to unsuitable accommodation, had his human rights ignored, an inquiry has found.
The report by the Health Service and Local Government Ombudsman highlighted failings in the care of the Newcastle man, known as Mr J, who has since died.
After hospital he stayed at a flat, where he was kept locked in.
Northumberland, Tyne and Wear NHS Foundation Trust and Newcastle City Council said services had now changed.
The investigation followed a complaint by the brother of Mr J, in 2006.
Previously, the man had been active, outgoing and sociable, living independently in rented accommodation with his wife and receiving day-to-day support from Newcastle City Council.
Following a deterioration in his skills and health, he was admitted to hospital for a short assessment and diagnosed with dementia and epilepsy.
Although declared ready for discharge, he was kept in hospital for a further five months.
Then, as his previous accommodation was considered to be unsuitable, he and his wife were moved to a self-contained flat at a care home for older people. The flat was locked to restrict his access to the outside.
Although intended as a temporary arrangement, he was still living there 10 months later when he became ill with a chest infection. The 53-year-old died in hospital.
The investigation found that Mr J's family were not fully involved in plans for his care.
'Quality of life'
The Health Service Ombudsman, Ann Abraham, said: "Mr J's rights, best interests, and family relationships were not taken into account when the trust and the council made plans for his care.
"This was highly likely to have had some impact on the quality of his life, and hence his wellbeing, in the last 18 months or so of his life.
"Mr J's family were also wrongly denied the opportunity to be involved and will never know if they could have made a difference to his quality of life in those last months, which must be a cause of significant and ongoing distress for them."
His family was awarded £2,000 for distress, which it has said it will donate to charity.
Local Government Ombudsman Anne Seex said: "The failures in Mr J's case show how public authorities can neglect a vulnerable person's wishes and basic human rights to liberty and family life.
"As a result, the authorities concerned will make changes so that other families are not treated this way."
Ewen Weir, Newcastle City Council's executive director of adult social services, said: "We fully accept the findings of the joint report and once again apologise unreservedly to Mr J's family.
"The events detailed in this report took place some time ago and our service, particularly in the way we deal with vulnerable people like Mr J, is now unrecognisable, and fully complies with government guidelines.
"However, we will continue to work hard, internally and with our partners, to make sure we continue to improve."
A spokeswoman for the Northumberland, Tyne and Wear NHS Foundation Trust said: "The introduction of the Mental Capacity Act in 2007 provides a robust framework to assess and record capacity and the best interests of the patient.
"This also includes the involvement of family members.
"The trust has also introduced a monitoring tool, 'How's it going?', where patients can express any concerns or ask questions about their care, treatment and environment."