Dennis and Mireille Gillings
The son of an East End fishmonger, Gillings, 73, built a top US pharmaceutical business. The academic, who got his PhD at Exeter University, launched his North Carolina company Quintiles and floated it in 1994 before taking it private nine years later in a £1.1bn deal. The operation merged with healthcare information giant IMS Health last year and the combined group is worth £14.4bn. Gillings and his Montreal-born wife Mireille, a leading Canadian biotech entrepreneur, retain a £706m stake.