In John Christopher's 1967 teen sci-fi classic The Tripods, the heroes Will and Fritz have just destroyed the 'Masters', an alien race which has taken over the Earth, when they meet some of their unfortunate slaves. These are people controlled by electronic 'caps' fused into their brains.

One of them rises up from the fallen body of his alien overlord and declares to his fellow-slaves, "The Masters are no more. Therefore our lives no longer have a purpose. Brothers, let us go to the Place of Happy Release". That refers, of course, to a euthanasia centre the Masters had thoughtfully provided.

Though I must have read this at least thirty-five years ago, it came to my mind when I first heard advocates of assisted suicide complaining that some people oppose assisted suicide for 'religious reasons'. This gets it precisely backwards, rather as if it were said that some people don't believe in kosher food, or in pilgrimage to Mecca, for religious reasons; for of course these are things which are believed in by one particular religion, for reasons specific to that religion, which obviously everyone else does not share.

The demand to be permitted to kill oneself, and have assistance provided to help do so, is similarly a peculiar belief of one particular religion. The religion in question is humanism, and the peculiar belief is in 'autonomy'.

The similarity to the Tripods scene is this: autonomy is, for the humanist, a master which must be served. In the ability to make choices which maximise pleasure is found the entire purpose of human life. And when that master, the all-powerful lord of autonomous choice, is found to be no more, then life is believed no longer to have a purpose. Suicide is the only thing left to do.

Now it might seem strange to speak of being enslaved by autonomy; isn't autonomy about freedom, the opposite of slavery? Yet it is part of the genius of Christianity to perceive that the opposite is in fact the case. Sin – autonomy from God – thinks it is gaining liberty but in fact finds slavery. The attempt to escape from the rule of God no more brings freedom than a plane escaping from its wings or a fish escaping from water. Those who set up autonomy as the master ethical principle do not find that it liberates them into a brave new world of happiness and fulfilment. Rather, they find that it locks them into a way of thinking which progressively dehumanises and destroys.

Nowhere is this clearer than with assisted suicide. The drumbeat of the argument of those campaigning for it is autonomy, autonomy, autonomy. It is the quasi-religious belief in autonomy which is driving the campaign for it and it is not hard to see why.

The adulation of our personal autonomy, the belief that our individual choices are the meaning and purpose of our lives, meets an impossible problem with the approach of death. For a while, the illusion (for that is what it is) of autonomy can be maintained by medical treatment which alleviates symptoms and postpones the end of life. But eventually the time will come when reality breaks through. Death is the ultimate negation of autonomy; it is a thing which comes upon us, and against which our will is entirely unable to stand. The approach of death is therefore a thing of horror to humanism, not only because of its utter hopelessness (a humanist funeral is one of the bleakest occasions it is possible to experience) but because it stands as an inescapable rebuke to the entire humanist project.

Once death has come close enough that its inevitability can no longer be ignored, the master whom the humanist has served all his life is found suddenly to be gone. Hence the complaint of pro-assisted-suicide campaigners that the dying at present 'have no good choices'. This is not so much a statement of reality (it is in fact entirely false) as a lament for a departed deity. The human with no further ability to choose has, in the humanist religion, no further value or purpose. The choices are no more. Therefore our lives no longer have a purpose.

Except one. There is one possible choice remaining, one way of refusing to bow to the irresistible power of death. It is to make the moment of death itself a choice, an exercise of the will. Like King Saul falling on his sword so that the Philistines would not overtake him, it seeks to avoid the shame of defeat by death by being the cause of death; thus maintaining to the last, even after it has ceased to have any plausibility, the belief that I am the master of my ship, I am the captain of my soul. By pulling the trigger myself (or pressing the button on the 'medical device', to use the term in the Leadbeater bill), I will keep the autonomy faith to the very end. Let us go to the Place of Happy Release. Before death can smother my ability to choose, I will cheat it at the last by choosing it myself.

This is why assisted suicide is such an article of faith for humanists. It is why Dignity in Dying has spent huge sums of money on tube adverts declaring 'When I cannot stay, let me choose how I go'. It is why Humanists UK says that UK laws should provide 'the choice to face the end of life with dignity and autonomy'. Note the total identification of those last two; dignity and autonomy are indistinguishable in the humanist religion.

And it explains the motivation behind those pushing for a change in the law. They are, almost universally, either explicitly or functionally humanists. And it explains why, almost universally, those who are not oppose it. It's not that they oppose it for 'religious reasons'; it's just that they don't share the one peculiar religious reason which drives it.

So the question is, why should the law of the United Kingdom be shaped by this one religious view? Particularly one both so fundamentally self-centred and so fundamentally bleak? Which can see no value or meaning in humanity other than that which we can self-generate by our own choices? And whose devotees are so in thrall to their master that they prefer death to the prospect of living without it?

Mercifully, the United Kingdom was founded, and constitutionally still stands, upon a far better foundation. One which understands that human life is not an individualistic project of self-creation but a precious gift from the God of infinite holiness and perfect goodness. Who made us to display his image, and entered our world to rescue us from our self-destructive attempts at autonomy, and to lift us to an inconceivable future glory. And therefore that human life is not an accident from which we must salvage some value by our own self-assertion against the brute facts of reality, but is a precious gift to be received from our conception and treasured for as long as it lasts. And so as we approach its end, we do not find our lives stripped of meaning but rather that their true eternal meaning and purpose comes into proper focus.

The question of assisted suicide therefore presents us with the question of whether we wish to replace that foundation with another, sprung from another religion, which demands suicide precisely because of its atrophied view of what human life really is. It is not a matter of whether Parliament should reject assisted suicide' on religious grounds. It is rather, whether it should accept it when it is demanded by one, and only one, religion, in the service of its own esoteric and destructive god of human autonomy.

Rev Dr Matthew Roberts is Minister of Trinity Church York and former Moderator of Synod of the International Presbyterian Church.