A majority of people in 21st century Britain neither hopes nor fears for a life after death. Only about a third believes in Heaven, and even fewer in Hell and the Devil.

Marriage is no longer seen as a sacrament and even church weddings no longer find favour.

Moreover, the existing trend towards secularisation seems almost certain to continue. The incidence of religious belief has declined sharply in recent decades and young people today are significantly less religious than their elders.

More than a third of today's young people describe themselves as either agnostics or atheists. Among middle-aged people and the elderly, the figure is far smaller.

Yet tradition and a sense of "the fitness of things" still maintain their grip on the British imagination.

Even in this secular age, a substantial majority of people - including thousands of non-Christians and non-believers - believes that the Queen should remain head of the Church of England and Defender of the Faith.

Repeating a question that the Gallup Poll asked nearly four decades ago, YouGov began by asking people, bluntly, whether or not they believed in God.

The findings, set out in the chart on Page 17, are startling. Whereas in 1968 more than three quarters of people, 77 per cent, said they did believe in God, that figure has fallen by nearly half to 44 per cent - a minority of the population.

The proportion prepared to admit that it does not believe in God has more than trebled from a mere 11 per cent in the late-1960s to 35 per cent today.

The gap between the number of believers and non-believers, once wide, has thus closed dramatically. As the figures in the chart also show, a majority of men, as well as a majority of young people, now decline to acknowledge the existence of God.

However, today's religious doubt frequently amounts to just that: doubt. One in four of YouGov's sample, asked to say whether or not they believed in God, replied "Don't know" and, even among the 35 per cent who said they did not believe in Him, considerably more described themselves as agnostics rather than outright atheists.

The nature of many people's beliefs also appears to be subtly shifting. Among the 44 per cent of YouGov's respondents who professed a belief in the Almighty, more than a tenth were clearly not monotheists in the usual sense, believing in one God and only one.

A fair proportion, three per cent, claimed to believe in more than one God and 10 per cent described themselves as believing in "some other kind of Supreme Being".

Against such a background of rising doubt and disbelief, it is unsurprising that most people recognised that Britain was becoming a more secular country, in the sense that fewer people than in the past were religious and fewer regularly attended places of worship. That view is held by no fewer than 81 per cent of YouGov's respondents.

But do they welcome that fact or regret it? A substantial proportion regrets it - a proportion that even includes roughly one in seven of professed non-believers.

Large numbers evidently feel that, even if they themselves are not especially religious, the country as a whole is poorer for having lost what was once a commonly shared faith.

The section of the chart headed "Religious beliefs" also attests to the gradual erosion of specific beliefs that once underpinned much of the greatest religious art. Roughly half a century ago, more than half of Britons still believed in a life after death. Today, fewer than half imagine that their souls will outlast their corporeal selves.

Similarly, only a minority now believes in Heaven and even fewer believe in the Devil. Curiously, the proportion believing in the existence of Hell has changed not at all since Gallup asked about people's belief or lack of it in the nether regions in the late-1960s.

Roughly a quarter believed in Hell then. Roughly a quarter still do. It may be that many people do not construe the idea of Hell in religious terms but, like the French philosopher Jean-Paul Sartre, see it as pervading the human condition.

A further measure of British secularisation is provided by the responses to YouGov's question about where people would like to be married. Within living memory, most people would probably have said - almost automatically - "in church". Not so today.

As the figures in the chart show, only 34 per cent of YouGov's respondents said they would like to be wed in a church or some other place of religious worship - a synagogue, mosque or temple. Nearly double that proportion, 63 per cent, would prefer not to be married in a place of worship at all (23 per cent) or else shrugged their shoulders and said indifferently that they "would not mind one way or the other" (40 per cent).

Needless to say, attendance at places of worship has declined correspondingly. Of the 44 per cent of YouGov's sample who professed to believe in God, hardly any were frequent worshippers and only a minority attended religious celebrations more than once a week or in most weeks. The great majority, like non-believers, mostly stayed at home.

As the figures in the chart indicate, Anglicans and adherents of one of the non-Christian faiths (only a small subset of YouGov's sample) were the least assiduous in their attendance. Nonconformists and other nonAnglican Protestants - and, to a slightly lesser extent, Roman Catholics - appeared, on the face of it, to be more devout.

In England, though not in Scotland or Wales, the Monarch has stood since the 16th century - and still stands - at the intersection between religion and the state. Despite the ongoing trend towards secularisation, only a minority of people seemed disposed to question this historic arrangement.

Only about one person in four reckoned that the Queen should no longer be allowed to play her role as head of the Church of England and a clear majority was evidently content that she should continue. Even among non-Christians and non-believers, the balance of opinion favoured the status quo.

However, the Prince of Wales's professed desire to be seen in future as "defender of all the faiths" is accorded a significantly less favourable response - both from Christians, many of whom undoubtedly believed that he should remain an exclusively Christian figure, and from non-Christians, many of whom almost certainly wanted to keep their religious faith to themselves.

As the figures in the chart show, majorities of Christians, non-Christian believers and non-believers are united in not wanting the prince, when he becomes king, to step outside the traditional royal role. That said, his "defender of all the faiths" concept was more widely applauded by people who were religious but not Christians than by others.

He appears to have struck something of a chord among that group, if not a very loud one.

As for religious education, a clear majority held that "the Government should encourage the parents of children of all faiths, including Christians, to send their children to the same schools" and only a tiny minority, five per cent, believed that the state should encourage the parents of children of minority faiths to send their children to separate "faith schools".

Others believed that the Government should support both non-denominational and faith schools but remained neutral on the issue of which type of schools children should attend.

Taken as a whole, YouGov's findings suggest that "live and let live" is the dominant British approach to religious belief as to so many things. The relative absence of religious passion in Britain probably helps to foster this country's atmosphere of easy-going religious toleration.

YouGov elicited the views of 1,981 adults across Britain online between Dec 16 and 18. The data have been weighted to conform to the demographic profile of British adults as a whole. YouGov abides by the rules of the British Polling Council.

--Anthony King is professor of government at Essex University