The post-Poppins supernanny returns thanks to capable screenwriter-star Emma Thompson, who’s set the story during World War Two when daddies are away fighting, and children man the home front. Down on the farm, Maggie Gyllenhaal’s Mrs Green is at a loss when her three terrors are joined by their posh cousins, evacuated from the threat of bombs over Kensington, though it’s not long before ex-military Nanny McPhee instils improving discipline. The mix is similar to the first film, naughtiness versus magic, but nimbler this time as it shuttles from class warfare to unscrupulous spivs (draft-dodging well-dodgy uncle Rhys Ifans) and the prospect of enemy attack. It’s bitty and rather light on mounting excitement, yet Thompson the writer smuggles in cheery elements of Enid Blyton and ‘A Little Princess’, the frolicking Old Spot piglets are a delight, and Nanny’s resourceful jackdaw Edelweiss a cult hero in the making. Director Susanna White, surely one to watch, manages some disarming emotional grace notes under the circumstances.