The east of England may be the most godless region of the UK, according to a "belief map" published by a theology thinktank today. Almost half of adults there believe the theory of evolution makes God obsolete, and more than 80% disagree with creationism and intelligent design, which propose that humans were created by God in the past 10,000 years, and that life owes its complexity to divine intervention.

The map was drawn up by the thinktank Theos following a survey of 2,060 people across the country who were chosen to be representative of the adult population.

The survey, which was conducted to mark the 200th anniversary of Charles Darwin's birth, found that nearly half of the British adult population could not name the country's greatest naturalist as the author of On the Origin of Species, the 1859 book that introduced evolution through natural selection to a sceptical Victorian society.

The poll also revealed some extraordinary views on more recent writings, with 5% of adults thinking Darwin wrote A Brief History of Time, a bestseller on the science of spacetime, which was written by the Cambridge physicist Stephen Hawking and is widely regarded as the most popular science book never to be completed by its readers.

A further 3% of those surveyed thought Darwin wrote The God Delusion, by the arch-atheist and Oxford biologist Richard Dawkins, while 1% thought Darwin was the author of The Naked Chef by Jamie Oliver.

The study found only 15% of people knew that Darwin was a self-described agnostic towards the end of his life, with a fifth believing he was an atheist. Nearly half thought evolution challenged Christianity but said it was possible to believe in both.

The survey suggests there is a widespread lack of religious sentiment across Britain. National average figures revealed that less than a third of adults see evolution as part of God's plan, 89% dismiss intelligent design and 83% reject creationism as plausible explanations for the existence of human life.

The survey reveals a relatively high proportion of people in London who believe in creationism. "Whereas the national average is 17% who believe that human beings were created by God in the last 10,000 years ... in London, that figure is 20%. That may well be due to the growth of Pentecostal churches in London, which are growing at an extraordinary rate," said Paul Woolley, director of Theos.

According to the survey, Northern Ireland has the highest proportion of people who believe in intelligent design (16%) and creationism (25%).

"The research clearly indicates there is a great deal of confusion about what people believe and why they believe it," said Woolley.

"There are two lessons in particular that we can learn from Darwin. The first is that belief in God and evolution are compatible. Secondly, in a time when debates about evolution and religious belief can be aggressive and polarised, Charles Darwin remains an example of how to disagree without being disagreeable," he added.