From the day when I was found to have kidney stones to the moment when a malignant tumour was removed from my neck (I had a parathyroid carcinoma, which fortunately is rare) I knew that every single one of the medical staff involved in the journey were helping me to live.  The doctor who diagnosed the stones, the radiologist who took the X-rays, the surgeon who cut out the cancerous growth: all their energies were concentrated to that end.

Every tale of illness is different but all, however they end, have something in common with mine: the medical staff in question are working for life – at least, if the patient has the “capacity” to take decisions, to borrow a word from Rob Marris’s Assisted Dying Bill, which will be introduced in the Commons on Friday.  Trust between doctor and patient will break down if they don’t, and the corrosion of that trust is inherent in the Bill.  In a nutshell, it would in some circumstances permit people to kill themselves with the active co-operation of a doctor (“the attending doctor”), the decision to do so having been endorsed by another doctor (“the independent doctor”).

The people in question are those with terminal illnesses who “are reasonably expected to die within six months”. To be told that you will be dead soon must be harrowing; the experience of the news sinking in even more so.  There is nothing in the Bill to prevent a doctor – a hospital doctor or one’s own GP – asking if you have considered assisted dying.  And there is nothing in it either to prevent the doctor who asks from being the doctor who acts – “the assisting doctor”.  The question would doubtless be phrased more delicately but it would be, in effect: “Would you like me to help kill you, or perhaps find another doctor to do instead?”

It is true that the Bill applies only to those with terminal illnesses – by the way, assessments of how long someone with one will live are often inexact – and that Marris has bunged in judicial oversight, which was absent from the original Falconer Bill on which his own is based.  But this is to make a nonsense of the ideology that drives the campaign for medically-assisted killing: namely, the belief that we should have autonomy over our own lives.  There is no good reason why such control should be confined to those with terminal illnesses who, rightly or wrongly, are believed to have less than six months to live.  However, a Bill that that set this out in plain view would frighten the horses – so the Marris Bill it is.

There will be shadow boxing during the next few days over polls here (which usually give the answer that their commissioners want) and experience abroad (there is no investigative system in Oregon, where deaths are running at seven times the original rate).  But the heart of the argument will be about pain and suffering.  The two are not quite the same – at least, if pain is to be defined as physical and suffering as psychological.  The Association for Palliative Medicine (AfPM) argues that suffering can be alleviated. As it puts it: “Someone’s suffering is unique and what a person says it is.  However, that person’s perception always has the potential to change and with expert care it usually does”.

At this point, it is worth standing back and asking of this Bill a question that should be asked of all Bills: why is it needed – especially given the rise of Living Wills? If the law were uncertain, and doctors were being prosecuted for easing the path of people in desperate pain at the request of their relatives, reform would be necessary.  But this is simply not the case.  Indeed, it was made clear five years ago that in such circumstances there will be no charges – as the main campaign supporting the Bill itself acknowledges.  Far from being uncertain, the law is clear, and works as a protection for elderly and vulnerable people: a mother, say, whose children are weary of her and impatient for money.

The Bill would abandon this certainty for buck-passing between the two doctors in question and the High Court.  The “independent doctor”, knowing that the High Court might over-ride his decision, could consequently feel able to take a punt on assisted suicide.  The High Court, noting that a doctor had approved a patient’s request, might well feel that it was in no position to second-guess the former: after all, clinical decisions are the province of doctors, not judges – a settlement that the Bill erodes.  Nor would the court have much time for investigations: the Bill urges decisions within a fortnight if possible.  It will also apply to England and Wales only.

Comparisons will be made with the 1967 Abortion Act.  Like the Marris Bill, it rested on the decision of two doctors.  Like Marris again, it provided for conscientious objection.  And like Marris yet again, debate was wrapped in the language of “safeguards” and “reassurance”.  It was not the intention of Parliament, it will be said, to usher in abortion on demand – which effectively now exists after 24 weeks – whatever one’s view of the issue.  But the comparison is in at least one sense misleading.  Embryos become children who become workers, funding public services through their taxes.  By contrast, older people are net gainers, not contributors.

One doesn’t need a maths degree to do the sums.  More older people equals more demand on health and social services equals higher taxes.  More assisted suicide – or “euthanasia by mouth”, as the AfPM calls it – equals less pressure on those services, and less pressure on tax rates too.  However limited assisted suicide would be if introduced, government would have an interest in expanding its reach.  On paper, this expression of individual autonomy looks plausible. In practice, it is less persuasive, unless one believes that the state will devote more care to safeguarding Britain’s vulnerable elderly than it did to, say, Rotherham’s vulnerable children – and many others.

The Bill is cautiously framed.  But doctors see where it’s going. The Royal College of General Practitioners, the British Medical Association, the Royal College of Physicians, disability groups – all oppose legalising assisted suicide.  During the last Parliament, the Government was accused of introducing major change to the NHS without a mandate.  But however ambitious Andrew Lansley’s Health Bill may have been, it didn’t upend the entire medical profession, as this one would do.

For if passed, it will divide doctors into two.  One group, the majority, will have nothing to do with assisted suicide.  A minority will differ.  Patients won’t always know which is which.  Perhaps league tables will come to the rescue, listing which doctors have helped to kill the most patients.  But only if MPs accept the logic of the Bill: that doctors should help to kill sentient people, in some circumstances, so junking the healing vocation that guides them.  Let’s hope they don’t.