Tommy Dreelan and family
Motor sport enthusiast Dreelan, 60, was raised in Wexford and moved to Aberdeen in 1977, starting his first oil-related company with his three brothers in 1986. After making £45.5m from its sale, the Dreelans developed the oil and gas services company Qserv, selling it for £165m in 2008. Spending and investment performance clips the family to £155m. Dreelan nows runs the sportscar team Celtic Speed.