the world's top physicists on hand, tributes were not hard to come by. "He's a very witty, humorous guy. It's amazing, under the circumstances, how he keeps his spirits up and brightens the atmosphere," said Nobel laureate and long-term friend Frank Wilczek, a physicist at Massachusetts Institute of Technology. "It's an inspiration that he's been able to control his world and make genuine scientific contributions under very difficult situations and keep up his good work. It's a fantastic human story."

Wilczek opened the scientific arm of the celebrations with one of his newest theoretical concepts – time crystals. Normal crystals are repeated patterns of atoms in the three dimensions of space. Wilczek's crystals are arrangements of matter that use the fourth dimension of time. "At first I thought ityears ago, told the Guardian: "I've met presidents of America, prime ministers, film stars and rock stars. You name them and I have probably met them. But this was the man who really took my breath away.

"As far as I'm concerned Professor Stephen Hawking is our generation's Albert Einstein. A lot of people who think they are very famous are going to be footnotes in history, but Stephen Hawking will not be a footnote, he is part of history. Like Einstein, Winston Churchill and even Margaret Thatcher."

Hawking's disease progresses through the steady destruction of the nerves that control muscles, leading to their wasting and weakening. Around 90% of people diagnosed with amyotrophic lateral sclerosis (ALS), the most common form of motor neurone disease, die within two to five