A long-time reader has been trying to convert me. He thinks it's time I dumped "the unbelievable and superstitious" and returned to the rational unbelievers' camp.

"The whole foundation of Christianity has collapsed for most thinking people," he chides. "Men are not turning away from one religion to take up another. They are turning away from all religion in their thousands."

I envy his certainty and it's nice he wants to save me. But I think he might be a little premature. Much like Nietzsche when he declared unequivocally that "God is dead".

And very like our own secular theologian - a contradiction in terms, surely? - Sir Lloyd Geering, who's been confidently predicting the death of Christianity and religion in general since the 1960s.

Geering, an ordained Presbyterian minister and theology professor, was "tried" for heresy back in 1967 for arguing, among other things, that the resurrection of Jesus - the entire basis for Easter, and many would argue, Christianity - need not be taken literally. He was a fan of the secularisation thesis that religion would inevitably be swept aside by the irresistible force of science, reason, progress and modernisation.

It wasn't, as it turned out. Globally, religion is winning and secularism is losing.

As Dinesh D'Souza writes in What's So Great About Christianity (2007): "This is the biggest comeback story of the 21st century.

"God has come back to life. The world is witnessing a huge explosion of religious conversion and growth ... The ranks of unbelievers are shrinking as a proportion of the world's population. Secularism has lost its identification with progress and modernity, and consequently it has lost the main source of its appeal."

Of the world's 6.8 billion people, 2.3 billion are Christians, 1.57 billion are Muslims, 800 million are Hindus, and 600 million are Buddhists.

"If secularisation were proceeding inexorably, then religious people should be getting less religious, and so conservative churches should be shrinking and liberal churches growing. In fact, the opposite is the case."

It's true that most of the Western World is becoming more secular. Only one in five Europeans says that religion is important in life, according to one survey.

In New Zealand, 45.5 per cent of people didn't declare any religion in the 2006 Census. Just under half the population (around two million) classified themselves as Christian (compared with 90 per cent in 1956), followed by Hindus (63,540), Buddhists (52,000) and Muslims (36,000).

Yet in the United States, where church attendance is trending downwards, 95 per cent of Americans, according to a 2006 Pew survey, still believe in God or a higher power.

And a recent Pew survey found that while Americans aged 18 to 29 were considerably less religious than their elders - they attended religious services less often, and fewer say religion is very important to them - in other ways they remained fairly traditional in their religious beliefs.

Some 64 per cent of young Americans had an absolute belief in God, 75 per cent believed in life after death, 74 per cent in heaven, 78 per cent in miracles, 68 per cent in angels and demons, and 59 per cent in hell.

Christianity is still the fastest-growing religion in the world (Islam is second, except in Europe), but its face is no longer white.

In 1900, more than 80 per cent of Christians lived in Europe and America, and just 10 per cent of Africans were Christian. Now 360 million (around 50 per cent) of all Africans are Christians. There are more churchgoing Presbyterians in Ghana than in Scotland, more Baptists in Nagaland, India, than in the American South, and more Anglicans in Nigeria (17 million) than in England (two million).

And despite the restrictions imposed by the Chinese Government, it is estimated there are now 100 million Christians in China who worship in underground evangelical and Catholic churches. China is projected to become the largest Christian country in the world.

Europe once sent missionaries out to the far reaches of Africa and Asia. Now, it's the other way round, with some 15,000 missionaries from Brazil, South Korea, China and Africa spreading the word in England.

The attraction goes beyond what some scientists suggest is hard-wiring in our brains that enables experiences of the transcendent - the so-called "God neurotransmitter".

As D'Souza writes: "For people around the world, the social landscape of the Bible is quite familiar. They, too, live in a world of hardship, poverty, money-lenders, and lepers. The themes of exile and persecution resonate with them. Supernatural evil seems quite real to them, and they have little problem in understanding the concept of hell."

Secularists might argue that this proves their point; that the less sophisticated populations of the developing world are more susceptible to religious belief than the rich Europeans.

But D'Souza suggests that what we are seeing is a rebellion against secularism. It's a "revolt into orthodoxy", as G.K. Chesterton wrote, a move back to traditional religion and away from the kind of arid, bloodless, godless theology of secularists like Lloyd Geering.

"Some scholars put this down to 'backlash' against secularisation, but this only begs the question: what is causing this backlash? The secularisation thesis was based on the presumption that science and modernity would satisfy the impulses and needs once met by religion.

"But a rebellion against secularisation suggests that perhaps important needs are still unmet and so people are seeking a revival of religion - perhaps in a new form - to address their specific concerns within secular society."

As German theologian Wolfhart Pannenberg puts it: "Secular culture itself produces a deep need for meaning in life and therefore also religion."