In 1975, Prof Hawking made his most important contribution to cosmology by proposin g that black holes emit tiny amounts of radiation - known as "Hawking radiation". Eventually, all black holes will evaporate.

However, his theory created a paradox. Prof Hawking also claimed that his radiation contained no "information" about the matter sucked into the black hole. Yet once the black hole evaporates, all information about the black hole is lost.

Under the laws of quantum mechanics describing the behaviour of the universe at the scale of individual particles, such information cannot simply disappear.

For 30 years Prof Hawking tried to get around the paradox by suggesting that the rules of quantum physics were different inside black holes - a solution that many colleagues were unhappy with.

Now, he has a solution, New Scientist reports today. The findings will be presented at a conference on general relativity in Dublin next week.

Although the solution has yet to be published, it was presented at a Cambridge seminar two months ago.

Dr Malcolm Perry, a Cambridge University theoretical physicist and a colleague of Prof Hawking, said the solution lay in the nature of a black hole's event horizon - the "point of no return".

Prof Hawking is proposing that the event horizons of black holes may not be "one-way streets" after all.

Although large objects would almost certainly be lost forever once sucked into a black hole, small amounts of information could gradually seep out over billions of years.

New Scientist also has a similar article. We'll probably have to wait till next week for more in-depth descriptions, discussion etc.