A Stanmore hospital nurse who hoarded a stash of unprescribed drugs died after overdosing on morphine, an inquest has found.

Priska Biyala, 47, was discovered by her half sister slumped face down on her bed at her halls of residence at the Royal National Orthopedic Hospital in Stanmore.

The South African national, who was an agency nurse at a number of hospitals in the capital, had taken a lethal cocktail of anti-anxiety tablets, pain killers and sedatives.

A package containing more than 100 unprescribed tablets addressed to a house in South Africa was also found in her flat.

Giving evidence at the inquest, held at Hornsey Coroners Court yesterday, Miss Biyala's half sister, Grettah Ntshangase, said her relative had been worried about her ill brother living in South Africa.

"She seemed well but was speaking a lot about her brother who is seriously ill back in Natal," she said.

"He had turburculosis which has also possibly HIV."

Mrs Ntshangase, also a nurse at Stanmore hospital, discovered the lifeless Miss Biyala on January 18 2007, after worried work colleagues said she had not turned up for her shift.

"I live in the same block as Priska in Henry Floyd Court at the hospital and had not seen her since January 15.

"Sometimes she works shifts at Kings College Hospital so I thought she could be working there but I went to see if she was in her flat after her bosses called me.

"There was no answer at the door so I went to her window and started banging but there was no response."

Mrs Ntshangase noticed the television was on so started shouting. She then noticed Miss Biyala's feet were hanging off the end of her bed.

"I got a stick and poked it though her window which was slightly open but she didn't move when I touched her with it and realised something was wrong."

Hospital investigators discovered some of the marked drugs in the package addressed to South Africa had come from Kings College Hospital.

Michelle Nolan, who conducted the initial probe, said: "We were not sure where all the tablets came from but on the balance of probability the unmarked drugs came from Stanmore."

Delivering an open verdict, coroner Andrew Walker, said: "We do not know why this medication was found in her system but there is no suggestion or evidence to support that she intended her life to come to an end."

After the inquest, an emotional Mrs Ntshangase said: "We used to share the family problems back at home because we were the only members of our family in the UK.

"We were very close to each other."