God no longer has any place in theories on the creation of the Universe, according to scientist Stephen Hawking in his latest book.
In a hardening of the more accommodating position on religion that he took in his 1988 international best-seller 'A Brief History of Time', Prof Hawking said the Big Bang was merely the consequence of the law of gravity.
'Because there is a law such as gravity, the Universe can and will create itself from nothing.
'Spontaneous creation is the reason there is something rather than nothing, why the Universe exists, why we exist,' he writes in 'The Grand Design', which is being serialised by The Times newspaper.
'It is not necessary to invoke God to light the blue touch paper and set the Universe going,' he added.
Stephen Hawking has achieved worldwide fame for his research, writing and television documentaries. He is renowned for his work on black holes, cosmology and quantum gravity.
In 'A Brief History of Time', Prof Hawking had suggested that the idea of God or a divine being was not necessarily incompatible with a scientific understanding of the Universe.
But in his latest work, he cites the 1992 discovery of a planet orbiting a star outside our own Solar System as a turning point against Isaac Newton's belief that the Universe could not have arisen out of chaos.
'That makes the coincidences of our planetary conditions - the single Sun, the lucky combination of Earth-Sun distance and solar mass - far less remarkable, and far less compelling as evidence that the Earth was carefully designed just to please us human beings,' he wrote.
Stephen Hawking argued earlier this year that mankind's only chance of long-term survival lies in colonising space, as humans drain Earth of resources and face a terrifying array of new threats.
He also warned in a recent television series that mankind should avoid contact with aliens at all costs, as the consequences could be devastating.
Stephen Hawking suffers from a motor neurone disease that has left him almost completely paralysed and dependent on a voice synthesiser.
Since 1974, the scientist has worked on marrying the two cornerstones of modern physics - Albert Einstein's General Theory of Relativity, which concerns gravity and large-scale phenomena, and quantum theory, which covers subatomic particles.
Last year he announced he was stepping down as Cambridge University's Lucasian Professor of Mathematics, a position once held by Newton and one he had held since 1979.
'The Grand Design', co-authored with US physicist Leonard Mlodinow, is due to go on sale next week.