Source, in full
At a King's College college feast, as quoted in 1949, John Maynard Keynes, 1883-1946, Fellow and Bursar, (A memoir prepared by direction of the Council of King’s College, Cambridge University, England), Cambridge University Press, 1949, page 37. This in turn quoted in Quote Investigator, "My Only Regret Is That I Have Not Drunk More Champagne In My Life", 2013-07-11