WPP: breaking up world's top advertising group could net £22bn

How Sir Martin Sorrell’s sprawling empire breaks down – and who could succeed him•Martin Sorrell’s resignation triggers 7% slide in WPP sharesSir Martin Sorrell’s resignation has raised the question of whether his successor will be able to stop a breakup of the world’s largest advertising group.A number of names have emerged as potential runners and riders, including the Informa chief executive Stephen Carter, who has worked at Ofcom, cable firm NTL and at WPP&