A retired doctor from Bath who was terminally ill with a degenerative brain disorder ended her life yesterday at a Swiss clinic in protest at Britain's outdated euthanasia laws.

Anne Turner died after drinking a mixture of barbiturates prepared by doctors at the Dignitas assisted suicide clinic in Zurich a day before her 67th birthday.

She was accompanied by her three grown-up children who supported her decision to end her life. Dr Turner was suffering from progressive supranuclear palsy (PSP), the incurable degenerative disease which killed the actor Dudley Moore in 2002.

Using her final hours to apply pressure on the Government for a change in the law, Dr Turner travelled to the Dignitas flat in Zurich, where 42 terminally ill Britons have ended their lives, accompanied by a BBC television crew and a clutch of reporters.

Her son, Edward Turner, 39, emerged from the flat shortly after her death at 12.35pm GMT and said: "She was ready to go and that makes it all the easier for us. We will respect her choice and we will miss her very much. We are very thankful that her suffering is over." He said she had fallen asleep within five minutes of taking the dose of barbiturates and was dead half an hour later.

Her daughter, Sophie Pandit, 41, an actor, said: "I was very glad it was peaceful. I'm so relieved that she's not suffering anymore but it is still a terrible shock."

The family arrived in Zurich on Sunday and attended a Beethoven and Rachmaninov concert, took a boat trip and rode the city's trams. At dinner they bought a bottle of champagne. "We had a good cry as we drank. Everyone in the restaurant was good enough not to stare at us," said Mr Turner, an accountant from London.

Yesterday morning at their hotel overlooking the Zurichsee, the city's major lake, Dr Turner said she remained determined to carry out the act. She was diagnosed with breast cancer in 2004 and had a mastectomy.

"I am just so tired of being dependent on people," she said. "But I have been forced to die in a strange country, not at home." Referring to her own failed suicide attempt in October, when she tried to suffocate herself, she said : "This time, it is really going to work. I do not want to go home."

The family then travelled by taxi to the Dignitas clinic at Forch, a few miles south-east of the city, for a consultation, which lasted an hour and 15 minutes, before driving to the flat, arriving at 10.30am. Mr Turner said the family "chatted, sang some songs and joked" in their final hours together. He also praised Dignitas as "superb", adding: "We are just full of admiration for the way they have helped my mother through this very difficult time."

Dr Turner was diagnosed a year ago and was at a relatively early stage of the disease - still able to walk, eat and communicate. She had prepared for her death by writing more than 100 "suicide notes" to her friends.

In a statement released after her death, she compared her situation to that of Dudley Moore. "At the end of his life he was unable to walk, talk, swallow or even blink. I do not want to end up like that." She said had been was forced to end her life sooner than she had wanted, because of the uncertain course of her illness, and called for assisted suicide to be made legal in Britain.

"In order to ensure that I am able to swallow the medication that will kill me, I have to go to Switzerland before I am totally incapacitated and unable to travel. If I knew that when things got so bad I would be able to request assisted suicide in Britain, then I would not have to die before I am completely ready to do so."

Her husband, Jack, a GP, died in 2002 from a similar degenerative disease, multiple systems atrophy.

Deborah Annetts, the chief executive of Dignity in Dying, said: "The Government must make time in Parliament for the Assisted Dying for the Terminally Ill Bill. Only this Bill could have prevented Anne Turner from taking her life early."