In Trevor Nunn’s Red Joan, Judi Dench stars as a suburban grandmother who finds herself at the centre of an international spy scandal in this decidedly passable war-time spy drama. Adapted from Jennie Rooney’s best selling novel of the same name, Red Joan was inspired by the real life story of Melita Norwood, an octogenarian who earned the nickname of  “granny spy” after being unmasked in 1999 as one of Britain’s longest serving KGB agents.

When Joan Stanley (Dench) is arrested at her home accused of passing state secrets to the Russians during the Cold War, the seemingly unremarkable old lady first appears dumbfounded by the accusations. Things, however start to unravel when we are transported back to Cambridge University in the early 1940s. Here, young science student Joan (Sophie Cookson) meets and forms an instant bond with Sonya (Tereza Srbova), an elegant Jewish Russian immigrant who has just fled Nazi Germany alongside her handsome cousin Leo (Tom Hughes).

Convinced by Sonya and Leo to join their leftist student group, Joan agrees to attend meetings, but shows little interest in their cause. Soon the young woman falls madly in love with the charming Leo who later confesses to being a communist spy, before being deported by the authorities. When she is offered a job on a top-secret government research project, Joan is again targeted by Leo who begs her to help share information with Russia to help prevent further conflict. Soon Joan is forced to chose between her conscience and allegiances to her country and new boss Max (Stephen Campbell Moore).

Disappointingly, Red Joan offers very little in the skullduggery stakes, preferring instead to focus on two instantly forgettable and fairly mundane love stories. Director Trevor Nunn (Twelfth Night or What You Will, King Lear) and screenwriter Lindsay Shapero offer a disappointingly contrived adaptation of a truly remarkable real life story.

Forgoing any kind of tension or suspense in favour of a soft focus view of one of the most perilous eras in history, the film ultimately fails to add anything of value to the original source material, beyond a couple of impressive performances courtesy of Dench and Cookson who can’t be faulted in their deliveries.

Elsewhere, Tom Hughes manages a great turn as Leo despite being saddled with a laughably unconvincing Russian/German accent. For his part, Stephen Campbell Moore brings his usual upper-class stiff-upper-lip schtick to a role which appears to demand very little else of him.

Trevor Nunn offers a deeply flawed and overly stagey production which is only just saved by an interesting premise. Perhaps too cosy for its serious subject matter, but remains very watchable nevertheless.