A dying patient had to ring a hospital switchboard on his mobile to ask for a glass of water, after nurses ignored his pleas.
Derek Sauter and his wife Susan on holiday in Portugal in 2007
From Sky News
By Steve Davies
Officials from the South London NHS Trust have apologised to the family of Derek Sauter, who later died in hospital of pneumonia.
The 60-year-old did not receive a "proper and professional standard of care" when he was admitted with a chest infection in June 2008.
A formal investigation is being conducted into his death, after it was found his oxygen levels went unchecked for 11 hours and were 35% lower than recommended.
Ruth Sauter, the patient's daughter, said she was disgusted by the treatment her father had received.
She told The Daily Mail: "His condition was not life threatening, and nurses had specific instructions to keep close tabs on him.
"'But their appalling lack of care, and cruel behaviour killed my father...It's so much worse knowing that he died alone, thirsty and scared on that ward."
After being admitted in the morning, he was given antibiotics and oxygen, but was later forced to ring his wife to tell her that he was not allowed any more water as he had earlier knocked over a cup.
After ringing the switchboard, a doctor was called to the ward, only for a nurse to tell him that the patient was "overreacting".
The hospital was unable to comment directly on the case, as it is part of the family's legal proceedings.
A spokeswoman said: "South London Healthcare NHS Trust would like to apologise to the Sauter family for the failings in care that Derek Sauter received.
"The trust believes that Mr Sauter did not receive a proper and professional standard of care that he and his family had a right to expect."