The universe was not created by God, scientist Stephen Hawking has said in his new book.
Professor Hawking believes the laws of physics were behind the Big Bang instead, in a challenge to traditional religious beliefs.
In The Grand Design, extracts of which were printed in The Times today, Prof Hawking concludes: "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.
"It is not necessary to invoke God to light the blue touch paper and set the universe going."
The book, co-written by American physicist Leonard Mlodinow and published on September 9, sets out to contest Sir Isaac Newton's belief that the universe must have been designed by God as it could not have created out of chaos.
He cites the 1992 discovery of a planet orbiting a star other than our Sun.
"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."
Prof Hawking had previously appeared to accept the role of God in the creation of the universe, writing in A Brief History Of Time in 1988: "If we discover a complete theory, it would be the ultimate triumph of human reason - for then we should know the mind of God."