A pensioner died in hospital after she was given ten times the correct dose of her medication.

Joan Dixon died of a poisoning after junior doctor Prashen Pillay wrote milligrams instead of micrograms on her prescrip- tion.

An inquest into the 77-year-old’s death began yesterday after police decided not to prosecute three people who were arrested on suspicion of manslaughter.

Mrs Dixon, of High Street, Findon, near Worthing, had mental health problems and was sectioned in 2010.

She fell and broke her hip in the Orchard ward of the Harold Kidd Unit in Chichester in September that year. She was treated in Ashling ward of St Richard’s Hospital, Chichester.

Dr Pillay was repeating a phase of his training at the hospital after failing to advance following a previous spell at the Royal Sussex County Hospital in Brighton.

On October 15 he found Mrs Dixon had an irregular heartbeat, a swollen calf and bladder problems.

Dr Pillay’s supervisor, Dr Shabana Khan, agreed he should prescribe intravenous digoxin, a drug which regulates the heart.

Dr Pillay said he understood he was supposed to prescribe 250 micrograms - but wrote milligrams instead. He told the inquest: “Somewhere between my brain and my right hand micrograms turned into milligrams.”

Under cross-examination he said he had not written out the word in full – as is NHS practice – because there was not enough roomon the prescription sheet.

It was later found that five 500-microgram containers of digoxin had been used on Mrs Dixon – equivalent to 2.5 milligrams.

The medics spent 15 minutes trying to find out how to counteract poisoning from an overdose.

Dr Khan said she tried to get on the NHS’s Toxbase website to find out how to give Mrs Dixon an antidote but could not access the site because she did not have a password.

Mrs Dixon started having a heart attack. She was taken to A&E but could not be revived.

A pathologist recorded the cause of her death as “digoxin toxicity”.

At West Sussex Coroner’s Court, sitting at Park House, Horsham, yesterday, Dr Pillay told Mrs Dixon’s family: “I want to say sorry. I really liked your mum. She was hard work but she was funny and I have to live with that for the rest of my life and my career.”

He pledged to “make it my life’s work to ensure this can’t happen again”.

Carolyn Dixon, Mrs Dixon’s daughter, thanked him for his apology. She had earlier criticised the care her mother received at the hospital, saying her mental health was not taken into account in their treatment of her.

She told coroner Penelope Schofield: “She was seen as a medical object and not as a whole person.”

She read a statement saying: “Like many of her generation she andmy father believed in the National Health Service, state education and the public good. She deserved better from the NHS.”

The inquest continues today.