Christians have warned against proposals to legalise assisted suicide in Scotland, saying that they could lead to vulnerable people feeling pressured to end their lives.

The warning followed the introduction of the Assisted Dying for Terminally Ill Adults (Scotland) Bill, which was put forward by Lib Dem MSP Liam McArthur on Thursday. 

The bill would open up assisted suicide to consenting adults who have "an advanced and progressive disease, illness or condition from which they are unable to recover and that can reasonably be expected to cause their premature death". 

It marks the third attempt to legalise assisted suicide in Scotland after a similar bill was defeated in 2015. 

Simon Calvert, a deputy director of The Christian Institute, said that people who are elderly, sick or disabled could feel like a burden on their families and the NHS.

"Removing end-of-life protections would make vulnerable people believe it's in everyone's best interests that their lives are cut short," he said. 

"It will hasten the deaths of thousands. Jurisdictions across Europe and North America have invariably seen eligibility criteria widening, often staggeringly quickly and the numbers of people dying rising year on year. Why would Scotland be any different?"

He said that efforts should instead be focused on improving the quality of end of life care. 

"Many with degenerative illnesses or incorrect prognoses have spoken of how glad they are that assisted suicide was not available to them because in their darkest moments they would have taken that option, and then missed out on years of making happy memories with their friends and family," he said.

"We ought to ensure that people in these difficult situations have access to the highest quality treatments or palliative care, rather than, as a society, telling them their lives are not worth living.

"I wish those campaigning so hard for sick people to commit suicide would invest their time and money in campaigning for improvements to healthcare instead."

Bishop John Keenan of Paisley, representing the Catholic Bishops Council of Scotland, called McArthur's bill "an attack on human dignity that introduces the idea into our culture that a citizen can so lose their value that society endorses their life as not worth living".

"Evidence from countries where assisted suicide or euthanasia is legal shows that up to half of the elderly and vulnerable who opt for assisted suicide did so because they felt pressured to end their lives through fear of being a burden," he said.

"For them the possibility of assisted suicide was less about having a 'right' to die and more about feeling the full weight and expectation of a duty to die. No law on assisted suicide can ever avoid laying such an unfair burden on our fellow citizens especially at the very moment they find themselves most vulnerable.

"When vulnerable people, including the elderly and poor, express concerns about being a burden, the appropriate response is not to suggest that they have a duty to die; rather, it is to commit to meeting their needs and providing the care and compassion they need to help them live."

Dr Gillian Wright, from Our Duty of Care (ODOC), an alliance of healthcare professionals opposed to assisted suicide, said the priority should be "well-funded, accessible, high quality palliative care for all". 

"The primary danger of assisted ­suicide is that individual lives are devalued by society because they are ill, disabled, confused or that their contribution to society is perceived to be minimal," she said. 

"The secondary danger is that ­terminally ill and disabled individuals may begin to devalue themselves because of the burden that they ­perceive they are to society. In a ­cruel twist, possible legislation on assisted suicide, that is designed to empower, may have the effect of eroding the autonomy of the most vulnerable."

Michael Veitch, Scotland Policy Officer at Christian Action Research and Education (CARE), said there had been no change to the "significant" body of evidence about the "dangers" of legalising assisted suicide since it was last debated in the Scottish Parliament. 

"In fact, it has grown significantly given events in jurisdictions such as Canada. If this practice becomes an option for patients in Scotland, the 'right to die' could become a 'duty to die' for those who feel they are a burden," he said. 

"Terminal prognoses are fraught. Coercion of patients is impossible to rule out, as is expansion of legislation," he said.

"Expert doctors warn that end-of-life care would be severely impacted. And disabled people warn that 'assisted dying' sends a regressive message about their quality of life. We urge MSPs in all parties to reject this bill at the earliest possible stage."

Chris Ringland, Public Policy Officer, of the Evangelical Alliance Scotland said he was "deeply concerned" about the implications of the bill and "the message it sends about how we value our family and friends who are at the end of their life".

"Rather than providing autonomy and freedom, this proposed law would fundamentally change our NHS and palliative care, creating disturbing anxiety for terminally ill patients about 'being a burden' by continuing to live," he said. 

"Our membership believes everyone is created equal in the image of God – and therefore terminally ill patients shouldn't have to think twice about whether their life is worth continuing."