The death of a healthy and active retired nurse who ended her life at a Swiss suicide clinic to avoid deteriorating in old age is a "deeply troubling" case that sends a "chilling message" about society's views of elderly people, a campaign group said.

Gill Pharaoh, 75, travelled to Switzerland last month to die as she feared growing old and being unable to kill herself.

The former palliative care nurse from Pinner, west London, was not seriously ill or suffering from a terminal disease but felt the quality of her life was declining.

In the weeks before her death last month she wrote on her blog that she was neither "whinging" about life nor "depressed", but was tired of the restrictions advancing age had placed on her, that her life was "complete" and that she was "ready to die".

Ms Pharaoh spoke of the frustrations of having tinnitus and losing her hearing, the physical inhibitions brought on by a bout of shingles five years ago that stopped her enjoying gardening and walking, and the "hundred and one other minor irritations" she felt left her with a poor quality of life.

She said: "Day by day I am enjoying my life. I simply do not want to follow this natural deterioration through to the last stage when I may be requiring a lot of help.

"I have to take action early on because no one else will be able to take action for me. The thought that I may need help from my children totally appals me."

The mother of two ended her life at the Lifecircle assisted-dying clinic in Basel on July 21, with her long-term partner John Southall at her side.

Before her death she told the Sunday Times: "It is not his (John's) choice at all and my kids are backing me, although it is not their choice.

"My daughter is a nurse and she said 'Intellectually, I know where you are coming from but emotionally I am finding it really hard', and I know she is."

Care Not Killing, a group which campaigns against assisted dying, condemned Ms Pharaoh's case as "deeply troubling".

A spokesman said: "It sends out a chilling message about how society values and looks after elderly people in the UK.

"It seeks the introduction of death on demand for those who fear becoming a burden, even if they are otherwise fit and healthy. This is an abhorrent development, but it reveals a truth that some who argue for a change in the law really believe there should be no safeguards or restrictions on assisted killing.

"Indeed this view was recently endorsed by Katie Hopkins who called for euthanasia vans to tour the country terminating the elderly and disabled, which she blames for the NHS financial crisis and bed blocking.

"Legalising assisted suicide and euthanasia will only serve to reinforce deep-seated prejudices that the lives of the sick, disabled and elderly aren't worth as much as other people's and lead to many similar cases.

"No wonder Parliament has repeatedly rejected changing the law and why we hope they will continue to do so."

But Dr Michael Irwin, co-ordinator of the Society for Old Age Rational Suicide, who helped Ms Pharaoh with her plans in Switzerland, said she had spoken of ending her life for about three years and that she was mentally competent and not depressed when she made her decision.

Dr Irwin, 84, a former medical director of the United Nations and ex-chairman of the Voluntary Euthanasia Society, now Dignity in Dying, said Ms Pharaoh had spoken of feeling her life was "complete", and suggested there were philosophical and intellectual arguments to be had around the issue.

He said: "I have many friends who feel like Gill does but are held back because of not much support from their families, religious issues and the tradition in Britain of having a stiff upper lip so we carry on regardless."

Dr Irwin highlighted comments made by Cilla Black, who said she would die happy if she were to pass away before any illness could rob her of being able to enjoy life and that 75 might be an OK age to die.

He said: "She (Black) made no secret of her desire not to linger in her old age and that is a bit like how Gill Pharaoh felt - she had had a good life, was active, had two wonderful children."

Black died overnight on Saturday in Spain and local police are investigating whether her death may have been caused by a fall from a dizzy spell.

Police believe she died from natural causes, and a post-mortem examination is being carried out today.