A "caring and loving" East Sussex mother helped end her long-suffering daughter's life following a 17-year battle with illness by handing her a lethal dose of morphine and a cocktail of drugs, a court heard today.

Bridget Kathleen Gilderdale, 55, passed two syringes filled with large doses of morphine to 31-year-old Lynn Gilderdale who injected the pain-relieving medicine herself in a suicide bid at the family home.

When it emerged that the dosage had not achieved Miss Gilderdale's suicidal aim, her mother searched the house for tablets which she crushed with a pestle and mortar and administered via a nasogastric tube.

In the hours that followed, Gilderdale, described as "devoted" to her sick daughter, gave her three syringes of air through an intravenous catheter with the intention of causing air embolisms.

Miss Gilderdale, who was struck down with ME - an illness that causes severe and debilitating fatigue - aged 14 and required round-the-clock care from her mother and carers, died later that morning, December 4, 2008, at home in Stonegate, near Heathfield, East Sussex.

Jurors at Lewes Crown Court were told Miss Gilderdale suffered from an "unimaginably wretched" illness and had expressed a clear desire in the past to end her own life.

But prosecutor Sally Howes QC told the six men and six women jurors that it was not their task to judge the "motives or morals" of her mother or "to choose where your sympathies lie".

"It is your job to decide whether the actions of Kay Gilderdale fell outside of the law," she said in her opening speech.

Gilderdale denies attempted murder but admits aiding and abetting suicide between December 2 and December 5, 2008.

Ms Howes said: "It is the prosecution's case that when Mrs Gilderdale realised that the two large doses of morphine that she provided to Lynn, that Lynn self-administered to try to end her life...instead of then realising that her daughter's suicide had gone horribly wrong, she then set about, over the next 30 hours, in performing actions which were designed with no other intention other than terminating her daughter's life.

"The further morphine, the further cocktail of drugs, the injecting of air - all designed to terminate her daughter's life. It wasn't done to make her better, it was done to make sure she died."

Ms Howes said the prosecution did not doubt that Gilderdale was a "caring, loving and most devoted" mother.

"We don't doubt that Lynn Gilderdale suffered from a profound illness with a quality of life which was unimaginably wretched and we do not dispute that Lynn had expressed a clear desire to end her life," she added.

"The question for you to consider is what the defendant intended by her actions during those 30 fateful hours - the last 30 fateful hours of her daughter's life."

More than a year before her death, Miss Gilderdale had accessed the website of Dignitas, the Swiss-based assisted dying group, and she had also instructed a solicitor to draft a "living will".

In it, she stated she did not wish to be resuscitated or subjected to any medical intervention if her quality of life was too poor, saying she feared "degeneration and indignity far more than death".

The court heard that the living will was counter-signed by the family GP, Dr Jane Woodgate, who said she was satisfied that Miss Gilderdale was of sound mental capacity at the time.

Miss Gilderdale was described as a very happy child in her early years and enjoyed sports and was a keen musician.

However, in November 1991 she contracted a viral illness, which was proceeded by ME.

Ms Howes said she suffered at first with panic attacks and spasms, and within four months was unable to move from the waist down and unable to sit up without losing consciousness.

She became totally bedridden, losing her ability to swallow which resulted in her being fed by a nasogastric tube.

Jurors heard she communicated through sign language which she developed with her parents, who were divorced but remained supportive of their daughter.

With her condition requiring numerous hospital admissions, Miss Gilderdale was said to have grown to distrust the medical profession and became heavily dependent on her mother and other carers.

A "turning point" for Miss Gilderdale's life occurred in October 2005 when she was admitted to the Conquest Hospital in Hastings to have her Hickman line, an intravenous catheter, changed under a local anaesthetic.

During the procedure, her lung was punctured and an artery was damaged, resulting in one lung filling with blood and the other filling half-way. She was placed on life support and transferred to King's College Hospital in London.

Unconscious for three weeks, her family said their goodbyes as it was feared she would not live but she survived.

However, Ms Howes said: "This traumatic experience and her lengthy hospital stay was a turning point and she had a subsequent wish not to be resuscitated if she was in that condition again.

Ms Howes said it was at about 8.30am on December 4, 2008, that Miss Gilderdale's father, former policeman Richard Gilderdale, telephoned Dr Woodgate's surgery informing her she had died.

Dr Woodgate arrived at the Gilderdales' home shortly afterwards and was told by Gilderdale the sequence of events leading up to the death. She told the doctor that her daughter called out to her, saying she felt she had not administered enough morphine.

Ms Howes said that Gilderdale spoke to her daughter for about an hour, telling her it was "not the right time" but Miss Gilderdale insisted it was time for her "to go".

At about 3am on December 3, Gilderdale gave her daughter two syringes of morphine, which Miss Gilderdale administered herself through her Hickman line directly into her vein.

"At about 6am, Kay felt that the morphine had not achieved Lynn's aim of killing herself and so Kay searched the house for tablets," said Ms Howes.

The tablets were crushed with a pestle and mortar and inserted into Miss Gilderdale's nasogastric tube.

Later at about 2am on December 4, Gilderdale gave her two or three doses of morphine directly into the Hickman line and later gave her three syringes of air.

Ms Howes said Gilderdale telephoned the assisted suicide organisation, Exit, in the hope of gaining further advice, and then gave Miss Gilderdale a further eight tablets.

Miss Gilderdale died at 7.10am that morning. There were no signs of struggle and no suicide note was found, Ms Howes told jurors. When Gilderdale was arrested on suspicion of murder, she gave no reply.

A post-mortem examination carried out at the Conquest Hospital found that the cause of death was morphine toxicity. Ms Howes said it was not possible to confirm from the blood sample the account given by Gilderdale to Dr Woodgate about how many drugs had been given.