Women are far more likely to believe in God than men, a major study of attitudes among middle-aged Britons has found.
Atheism and agnosticism are the majority creed among the male population, but almost two thirds of women believe in Heaven or an afterlife, according to the study which has been tracking 9,000 people, now in their early 40s, for more than 25 years.
The findings also suggest that Muslims have by far the strongest faith in modern Britain, with Christians from smaller evangelical churches the only group coming close to the same levels of certainty.
Only one in six members of the Church of England or the other main Protestant denominations says they believe without doubt in God.
Just a third of Roman Catholics said the same, compared with 88 per cent of Muslims and 71 per cent of those categorised as evangelical Christians.
But the findings also point to major confusion among the population about beliefs and what even constitutes religion - with a quarter of those involved in the study changing their minds over the years on the basic question of whether they would say they had had a "religious" upbringing.
More than a quarter of those sampled fell into a middle category of so-called "fuzzy believers", who either said they believed in a vague "higher power" but not a specific deity or that they believed in God or a god "some of the time".
It also showed that beliefs in God and the concepts of Heaven and Hell no longer go hand-in-hand, with a quarter of those classed as agnostic still holding out hope for life after death and almost a third of religious believers rejecting the possibility of an afterlife.
The stark divide between the sexes on matters of faith emerges from the latest tranche of findings from the 1970 British Cohort study, published in the journal Longitudinal and Life Course Studies, which has been surveying the same people from mainland Britain born in 1970 since they were 16.
Overall, 38 per cent of women said they believed in God, notwithstanding some doubts, but only 24 per cent of men.
When asked about Heaven and Hell, 61 per cent of women said there was definitely or probably an afterlife, compared with only 35 per cent of men.
Prof David Voas, of the Institute for Social and Economic Research, University of Essex, analysed the data. He said: "Quite generally we find, across different times and places, that women are more religious but exactly why that is the case remains the subject of debate.
"The two main schools of thought are on the one hand to do with the different social roles and functions of the sexes and on the other more like genetic dispositions, it is a nature-nurture problem."