A grieving mother who is not satisfied with the investigation into her daughter's death has launched a legal bid for a fresh inquest.

Kathleen Corr's daughter Lisa Cummings was found in hospital with a ligature around her neck three years ago.

But a consultant neuropathologist claimed he had found no marks on her neck or body and said she had probably died from vasovagal inhibition, in which pressure on a certain part of the neck leads to almost instant death.

Now Mrs Corr is suing Roger Stone, the coroner for West Sussex, and seeking an order quashing the open verdict which he recorded, forcing him to hold another inquest.

The writ was issued by Powell Spencer and Partners based in London where Miss Cummings' brother Alex Cummings lives.

The coroner's office declined to comment.

Lisa Cummings, 30, who suffered from long-standing mental health problems, was found dead on the floor at The Dene Hospital in Goddards Green, Burgess Hill, on June 7, 2004.

She was found by hospital staff during a routine inspection and was discovered lying on her back with the cord from her pyjamas around her neck.

At the original inquest in Haywards Heath the same year her mother made an emotional outburst and blamed the hospital for her daughter's death.

She left the inquest after saying: "Why wasn't something done?

"I can't take it! I can't take it!"

Crying, she walked to the door, banging her fist on one of the desks and said: "Something should be done and done now.

"She would be alive if it wasn't for the hospital."

Lisa Cummings had been at The Dene since 2001.

Doctors had thought she was improving and had hopes that one day she might be able to rejoin the community.

She had been treated in various hospitals over the past 15 years and suffered from disturbed behaviour including swallowing money and batteries.

She had been treated with medication, the inquest heard.

She had heard voices telling her to bang her head against walls, and had put ligatures around her neck.

Miss Cummings, who often said she wanted to leave the hospital, had had schizophrenia diagnosed.

A care worker said her mood had darkened on the day of her death.

She was found dead 15 minutes after another inspection to check on her condition.

Dr Peter Wilkins, a consultant neuropathologist at St George's Hospital in Tooting, London, had told the hearing that the lack of marks on her neck and body suggested she had died from vasovagal inhibition, in which pressure on the neck stops the heart and causes death almost instantly.