Another Bill seeking to legalise assisted suicide has had its first reading in Parliament this week.
The Bill says assisted suicide should be made legal for those in "intolerable suffering" due to terminal illness, and with less than six months to live.
Opponents of the Bill have accused supporters of spreading "propaganda".
The Care Not Killing coalition has warned that "many, many vulnerable people will fall victim to a law which fatally discriminates against them."
"The Bill seeks to make it legal for doctors to assist terminally ill patients to kill themselves. But in striking down the present law, the Bill would eliminate the only true safeguard against abuse and lead to vulnerable people feeling under pressure to commit suicide," it said.
"And the Bill ignores the remarkable strides that have been made in pain relief for terminally ill patients, or that palliative care treatment in the UK is among the best anywhere in the world."
Writing in The Telegraph, Baroness Campbell said the best way to support the terminally ill was through better investment in palliative care, and by redressing the social care crisis.
"Despite what the propaganda says, the majority of people it is intended to help didn't ask for it and don't want it. In fact we are fearful of any change in the law that would weaken the protection we rely upon now," she said.
Under UK law, assisting someone in taking their own life is a crime carrying a prison sentence of up to 14 years. Many Brits have got around this by travelling to the Dignitas clinic in Switzerland.
In addition to Switzerland, assisted suicide is already legal in Belgium and the Netherlands, where critics warn that the laws have only expanded far beyond their original remit to include people with mental health issues. Both countries permit euthanasia for minors.
Last year, Dutch MP Pia Dijkstra called for the law to be changed further so that euthanasia would be available for healthy over-75s who are tired of life.
Spain became the latest European country to legalise euthanasia. Laws passed in March permit it for people with serious and incurable or debilitating diseases.