At 75, Joan Bakewell’s long and successful career as a journalist has culminated in the publication of her first novel, which she stresses is “grounded in fact”. It all began when she uncovered an old school magazine that described the Ship Adoption Scheme, an idea that would boost the war effort during the Second World War.

Schools would be paired with ships of the Merchant Navy that brought needy supplies across the Atlantic through the German blockade and back to Britain.

Bakewell interweaves two narratives. The war is going badly. Miss Cynthia Maitland, the “tall, straightbacked headmistress”, tells the pupils and teachers of Ashworth Grammar School, near Manchester, they will adopt SS Treverran and so support the brave men “confronting the enemy, surrounded by the turmoil and fear of war”, a war that had been going on for two and a half years.

It is 1942 and Captain Josh Percival and three of his crew visit their newly adopted school, where they are welcomed by the elegant headteacher.

It is not long before the sixth formers, Polly and Jen, fall for two of the sailors. To her surprise, the upright but lonely Cynthia falls in love with Josh, the rugged but married captain. After an agonising period of yearning, they finally meet in a dingy hotel and have an affair that will change their lives, with far reaching consequences for both families.

A second parallel story takes place in 2003, when Britain is about to invade Iraq. Millie, a bright historian, recently widowed, finds a basket of wartime memorabilia that belonged to her late mother — or did it? Thereby hangs the mystery of her birth.

Not only is she caught up in the story of her background, but she also finds herself in a further quandary. Will she have the courage to donate her kidney to her much loved grown-up daughter, who is on dialysis, has polystic kidney disease and is, as it happens, totally against Blair and his warmongering?

It is a pity that Blakewell does not tread a more delicate line between history and fiction.

She is more at ease when she steps back from her scrupulous research, endless period details and the deprivation of wartime Britain as she desperately as tries to capture the spirit of the times.

Despite her rather cliched characters, her tender love story is moving. She is also especially good on the vivid and horrendous sinking of the Merchant Navy ship torpedoed by a U-boat, when a few survivors manage to reach the lifeboat.

n Joan Bakewell will speak at the closing dinner of the Oxford Literary Festival with Paddy Ashdown, whose biography is due for release next month, on April 4.