British Gas is reviewing its estimated GBP55 million planning and buying account in one of the biggest UK media pitches so far this year. Dentsu Aegis’ subsidiary, Carat, has held the account since 2002, when it picked up the consolidated business after a pitch against ZenithOptimedia and OMD UK. OMD had previously handled the bulk of the business. In 2010, Carat successfully defended the account after a final shoot-out against ZenithOptimedia and Mindshare. Carat's sister agency, iProspect, handles digital.