And he urged the graduates sitting before him in the Younger Hall to follow their dreams too.

Earlier, Professor Peter McKiernan, of St Andrews University's School of Management, listed the athlete's "legendary record" and described him as "the most successful track cyclist the world has ever seen."

As he responded, Sir Chris - who received the honour from another Olympian, university chancellor Sir Menzies Campbell - said it was a day he never thought would come.

He told fellow graduates:"This a fantastic day for me, it's a huge honour to be here.

''Almost 14 years ago, I walked away from St Andrews'' . . (where he read maths and physics before transferring to Edinburgh, where he graduated with a BSc honours in sports science in 1999).

"To leave in second year, and all the friends I had here, was a choice I made purely for my sporting ambitions. I knew I would have to move away from the place I loved.

''It was a very difficult thing to do, one of the hardest decisions I ever made in my life. I suppose I was just following a dream.

''There was no certainty, no guarantee I would become successful. I just wanted to see how far I could go. I suppose it was a bit of a gamble really.

''I learned that, if you follow your dream and really pursue it and don't give up, you can achieve amazing things.

''But this is about you guys. It's really the end of one chapter and the beginning of another. You are well equipped to do whatever you want to do.

''However crazy the dream is, don't let people put you down.
''If you work hard, anything is possible."

That was a sentiment echoed in the graduation address given by Professor Pat Willmer, of the university's School of Biology.

Remarking that, in these troubled financial times, investing in education could be "the only investment that pays off at all," she urged the graduates from the Faculties of Medicine and Science, to go on learning and gaining wisdom.

Acknowledging they were entering a world where the future was not certain, she urged: "If every graduate here takes on an issue where there is imbalance, inequity or unsustainable progress, you can change things.

''We can just as easily have a society and an economy that is based on healing the future, instead of messing it up."

Other honorary graduates of the university last week included concert and opera singer Madame Margaret Marshall, (Doctor of Music); Fijian Ms Taufa Vakatale who has been instrumental in breaking down barriers for women from the Pacific countries (Doctor of Letters); major local cancer fundraiser, Jacqui Wood (Doctor of Laws); writer Stephen Donaldson (Doctor of Letters); the Rt Rev Dr Nicholas Thomas Wright, Bishop of Durham (Doctor of Divinity); Professor David Pines, international scientist and science statesman (Doctor of Science); and Dr Vartan Gregorian, president of the Carnegie Corporation of New York (Doctor of Letters).