Neglect by medical staff contributed to the death of a hospital patient who died from dehydration after calling 999 because he was so thirsty.
Kane Gorny, 22, from Balham, south London, died at St George's Hospital, in Tooting, in May 2009.
The inquest heard a nurse failed to give him his diabetes medication and police were sent away when they responded to his call.
"A cascade of individual failures" led to his death, the coroner said.
Mr Gorny, a supermarket employee, was suffering from diabetes insipidus, which leaves the kidneys unable to conserve water.
He was undergoing a hip replacement at the hospital after steroids had weakened his bones.
Mr Gorny had previously recovered from brain tumour but since the treatment he was prone to violent behaviour, the inquest heard.
The day before his death, he was sedated and put in a side room after his condition caused him to be aggressive towards nurses, the inquest heard.
A post-mortem examination found dehydration caused high sodium levels to lead to his death.
Recording a narrative verdict at Westminster Coroners' Court, deputy coroner Dr Shirley Radcliffe said: "Kane was undoubtedly let down by incompetence of staff, poor communication, lack of leadership, both medical and nursing, a culture of assumption."
The coroner added that the team caring for him failed to involve the hospital's endocrinology team to monitor his fluid balance.
In a statement read out by their lawyer, James Stevenson, Mr Gorny's family said he was "well-liked and adored" as a son, brother and friend.
Mr Stevenson said: "The tragedy of his death is that he had fought and overcome terrible adversity at such a young age and was very much looking forward to a bright future.
"Having listened to the evidence over the last four days, we as a family have been devastated to hear of the number of missed opportunities to avert our son's tragic death.
"We are pleased the coroner's verdict of neglect recognises the number of systemic and individual failures in the basic level of care provided to Kane."
Dr Rosalind Given-Wilson, the medical director of St George's Health Care NHS Trust, said it was "profoundly sorry".
She said: "We deeply regret the death of Kane Gorny, and have apologised unreservedly to his family for the grief that this has caused.
"We provide safe high-quality healthcare services to over a million patients across south-west London every year, but it is clear that on this occasion our services fell short of expectation in a number of respects, and for this we are profoundly sorry.
"We have admitted civil liability for the failures in Kane's care and we accept the coroner's verdict.
"We have made changes to senior leadership on our wards and put a number of patient safety measures in place."
Mr Gorny's aggressive behaviour had "blinkered" the staff caring for him and nurses felt he had a "fixation" with water, the inquest heard.
Dr Radcliffe said staff nurse Sharon Gibbs was "out of her depth" and should have sought help from seniors.
Describing Mr Gorny's family as "incredibly stoic", the coroner added: "I have been with this case for two years, and it has always been a very difficult case for me to think about, it is such an emotive one."
A Department of Health spokeswoman said: "This is a very tragic case. Every patient expects to receive safe and high-quality care, and to be treated with compassion.
"There is no excuse for any hospital to be providing poor-quality services for patients."
She added that the government had set up the Nursing and Care Quality Forum, to make sure that the best nursing practice runs throughout the NHS.
"We want to introduce patient-led inspections and put regular nursing rounds in place to check that patients are always comfortable, properly fed and hydrated, and treated with dignity and respect," she said.