Diageo’s shareholders are urging the embattled drinks company to prevent the finance director from leaving after he was passed over for the chief executive job in favour of Sir Dave Lewis. Investors want Nik Jhangiani to stay on at the drinks business, which makes beverages from Guinness to Johnnie Walker, to create what one long-standing investor called a “box office blockbuster” duo to revive the former FTSE 100 star.