Police launched an investigation after nurses allegedly ignored a “lively and caring” young man as he died of dehydration at St George’s Hospital.

Kane Gorny was so desperate for a drink he rang the police, but when officers arrived at the hospital they were told everything was under control.

The 22-year-old needed regular medication to keep him hydrated, but nurses allegedly forgot and called security guards to restrain him when he made a fuss.

His mother, Rita Cronin, said: “They ruined my life. I will never rest until I have justice for my son.”

Mr Gorny, of Weir Road, in Balham, worked for Waitrose in Wandsworth and had been a keen footballer before he was diagnosed with brain cancer.

His treatment was successful, but the drugs he took weakened his bones and he was admitted for a hip operation in last May.

His mother said he needed medication three times a day to control his bodily fluids because of a pituitary gland problem.

She said the night before he died, on May 27 last year, lab staff testing his blood found dangerously high levels of sodium – indicating an imbalance of fluids.

But the nurse responsible for passing the message on allegedly went off duty.

The next morning, Ms Cronin found her son delirious, but said nurses ignored her pleas for help.

A ward doctor later passed by and immediately raised the alarm when he saw Mr Gorny.

His inquest at Westminster Coroner’s Court was opened and adjourned when Dr Shirley Radcliffe, the coroner, referred the case to the police.

A hospital spokesman said after a full investigation there was now a greater level of night nurse leadership, more experienced staff on night duty, and a new method of handover had been implemented to ensure information was communicated properly.

He said: “We are extremely sorry about the death of Kane Gorny and understand the distress it has caused his family."