The donation, by Swedish-born Hans Rausing, co-founder of the packaging firm TetraPak, will fund around one tenth of the project, the university said yesterday.
Mr Rausing, 71, Britain's second richest man, after being knocked from the pinnacle of the wealth league this year, was reportedly inspired to make the gift by an enthusiasm for cosmology and the work of Cambridge professor Stephen Hawking.
Cambridge owes a debt of gratitude to punitive Swedish tax laws, which prompted Mr Rausing to leave his home country in the 1980s and settle in Britain.
He and his brother, Gad, became richer than the Queen in 1995 thanks to their carton - an invention inspired by their grandmother's sausage- making, in which meat was squeezed into a skin and pinched at both ends.
Since selling his stake in the Swiss-based packaging group Tetra Laval last year for almost pounds 3bn, he has retired to his West Sussex home, set in a deer park, and indulged his passion for vintage cars.Reuse content