LONDON, Nov 30 : Humans will have to colonise planets in far-flung solar systems if the race is to survive, renowned physicist Stephen Hawking said in an interview on Thursday as he was awarded a top honour.

''The long-term survival of the human race is at risk as long as it is confined to a single planet,'' he said in a radio interview with the British Broadcasting Corp. ''Sooner or later, disasters such as an asteroid collision or nuclear war could wipe us all out. But once we spread out into space and establish independent colonies, our future should be safe.''

Because there are no other planets like Earth in our own solar system, Hawking said humans will have to travel to another star to find a hospitable planet to colonise. At the speed of chemical-propelled rockets like the Apollo, the trip to the next nearest star would take 50,000 years, he said.

Hawking, 64, whose speech and mobility have been limited to a speech synthesiser and wheelchair by the progression of Lou Gehrig's disease, gave an interview to the BBC on Thursday before receiving an award from the Royal Society.

The Copley medal is the world's oldest award for scientific achievement, first awarded in 1731. Charles Darwin, Albert Einstein, Louis Pasteur and Sir James Cook also have received the award.—AP