David Green QC begins his new role as the director of the Serious Fraud Office today, following Richard Alderman’s retirement. Green, a barrister with 25 years’ experience in criminal law, was until last year director of the central fraud group of the Criminal Prosecution Service. While his move to the SFO had been expected since December, the new director comes at a turbulent time for the enforcement body. Last week Alderman’s second-in-command, chief executive Phillippa Williamson, quit suddenly with no reason given for her departure. The SFO has come under fire in recent months for its handling of some cases.