One of the paradoxes of the modern, secular age is the lingering strength of the sacred. Although most people long ago ceased to have any connection to organised religion, the instinct to defer to faith leaders on certain life and death issues remains a powerful one. Church leaders and other clerics make good use of this unconscious genuflection, which is why they will be expecting politicians to pay close attention to their joint letter to Parliament, urging MPs to vote against the Assisted Dying Bill.

Referring portentously to their “sacred calling to care for the most vulnerable in society”, the clerics claim that half-a-million elderly people in Britain could come under direct pressure “to end their lives prematurely” if the Bill, which goes to debate this week, is passed.

The list of signatories to the letter, sent to every MP, reads like a who’s who of contemporary British religion, ranging from the Anglican and Catholic archbishops to the secretary general of the Muslim Council of Britain and even the Zoroastrians. The point is made: faiths speak as one on this issue and they do not accept that doctors under any circumstances should help a patient to die.

No one denies that bishops, imams, rabbis and all the rest have the right to contest important changes in the law, especially when they clash with their most closely held beliefs. If you believe that all life comes from God, then it may be reasonable to argue that only God can take away what he created. In that case, every illness, no matter how painful, disfiguring and destructive, must be endured to the bitter end and the doctor’s only duty is to ease the patient’s suffering before that last dying breath is drawn.

The letter from the religious leaders in that context is simply an act of duty on their part. What is much more problematic is the assumption that everyone else should heed the clergy on this point, even when the vast majority of the public do not go near a church and do not see their lives as some kind of gift that needs to be returned to sender.

A generation ago, when it was still possible to talk in general terms of Britain as a Christian country, the argument that the churches had an automatic right to be consulted closely over any laws that infringed on the “sacred” had some force to it. Today it does not. Only about 12 per cent of the population of the UK go to church, which makes us religious fanatics compared with Norway, where the figure is 3 per cent, but still leaves almost 80 per cent of population who do not attend churches, synagogues, mosques or temples except perhaps for weddings and other rites of passage.

MPs should keep those figures in their minds when the debate on the Bill begins, and on the fact that although we talk a good deal about choice and rights, people suffering from terminal illnesses are still denied the right to make what most people would consider a fundamental choice – which is whether they must continue battling their illness to the end or not.