I also learn from the same source that Sir David used to accompany Dusty Springfield on the trumpet. That was in the Sixties, mind you. Sir David, 63, was also an accomplished guitarist and used to hang around louche London clubs playing jazz. Then in 1965 he bumped into Sigmund Warburg at a party and went into merchant banking. The rest is history.
Whether Sir David will now "do a Nigel Lawson" and write a diet book remains to be seen.
The ex-colleague adds that Sir David ran a lucrative roulette game while at Oxford University together with Peter Wilmot-Sitwell, a fellow ex- Warburger and Close Brothers director, and Stuart Wheeler, founder of City betting company IG Index.