A director of Tesco has begun drawing up a list of possible successors to the beleaguered chairman of the UK's biggest retailer as it battles to contain the fallout from a A 250m accounting crisis. Sky News has learnt that Patrick Cescau, who serves as Tesco's senior independent director, has told leading investors in the last week that the company is preparing for a range of scenarios, including the exit of Sir Richard Broadbent.