Maria Caulfield is MP for Lewes.

Some of the strongest opposition to assisted suicide comes from elderly people, people with disabilities, and those who are some reason or another vulnerable – sufferers from chronic illness are one such group. Their central objection to the introduction of assisted suicide is that it radically undermines their cultural, medical and legal protections. Each of these is immensely important if we are to treat frail and dependent ill people with the dignity they deserve. My experience as a nurse, working with many terminally ill people, showed me just how easy it is for a frail, terminally ill patient to feel a burden or an inconvenience – and how vulnerable this makes them to pressure, however subtle or implicit, that they’ve ‘had their time’.

Those who support assisted suicide are quick to reassure doubters with talk of “safeguards” – such as a cooling-off period before a request for assisted suicide is granted, checks by more than one doctor, limits on who can be given lethal drugs to end their life, and so on.

There is, however, a fundamental problem with such proposed measures – and it is this: they cannot detect subtle coercion by family or friends of terminally ill people, nor can they detect whether a person is only asking for assisted suicide because they feel they ought to do so or because they feel pressure from some source or another. The fact is that assisted suicide will affect people’s own perception of the value of their life. The decisions and choices that people make do not occur in a vacuum; especially in the medical context, in matters of life and death, individual patient’s decisions about care take place in a tight web of expectations and attitudes.

By offering killing as a treatment option, we change that web. We force people to consider whether their lives are worth living – a quite unconscionable thing to do. There is a very great danger that naturally unselfish people come to regard ending their own lives as the right and selfless thing to do, regardless of whether they really wish to die or not. This is especially perilous as we move into an era of huge financial pressure on the health service in general, and care for the elderly and chronically ill in particular.

Additionally, experience and human psychology suggests that, however well-intentioned, it is very easy for safeguards to become a box-ticking exercise; that is, the authorisation procedure for assisted suicide is treated as a series of hurdles to overcome to reach a predetermined goal rather than a genuine impartial assessment of an individual situation. It is clear, for example, that this has happened with the Abortion Act. The scandalous revelations about presigning of abortion forms that emerged last year are the most obvious example of how an authorisation procedure that looks scrupulous and rigorous on paper is next to useless, if not taken seriously by the people who are supposed to be following it.

Assisted suicide is above all a problem of public safety, for the reasons outlined above. It’s not simply that the currently proposed safeguards are inadequate (though they are) but, rather, that it is perhaps impossible in principle to create a safe system in which doctors are sometimes permitted to kill their patients. Once we have conceded the legal and ethical principle that killing can be a treatment option, it is very hard to control the further application of that principle. The genie is hard to get back in the bottle.

It is important that we do not let the huge emotional impact of very hard cases blind us to the fact that a change to the law is a change for everybody all over the country, and so must be considered dispassionately and with a true regard for the issues at stake – the protection of the vulnerable, the preservation of a medical culture that errs on the side of life, and the future of palliative care.

So opposition to assisted suicide is not simply a religious issue. I have heard a lot of extraneous and frankly silly arguments about a handful of religious believers blocking much-needed civilised reforms which are supported by rational secularist people everywhere. But that is a false portrayal of this debate, and one which has been refuted so many times that it is hard to know why people continue to perpetuate it. Assisted suicide is opposed not simply by people of faith – Lord Carlisle, for instance, one of the leading opponents of assisted suicide in the House of Lords, is not a religious believer, and nor are disability rights campaigners such as Liz Carr and Baroness Jane Campbell.

We must listen to the voices of those who have most to lose from a law that calls into question our long-standing and unconditional legal and medical protection of the disabled, elderly and infirm. I urge everyone interested in this debate to read the testimonies of people such as Baroness Tanni Grey-Thompson about the huge challenges faced everyday by people with disabilities and life-limiting conditions; discrimination, thoughtlessness and abuse. Let’s forget about assisted suicide, and focus on assisted living. Let’s make sure we are a society where people with serious illness and disability are able to live, not where it’s made easy for them to die.