The Secret Guests by BW Black review – John Banville’s royal yarn

In The Secret Guests, BW Black – AKA Benjamin Black, AKA Irish novelist John Banville – gussies up a wartime rumour of royal jiggery-pokery into a fanciful yarn that has just enough plausibility to see it home. Time was when such speculative mischief might have given them conniptions at the palace; nowadays the royals are surely too busy tearing their own reputation apart to notice a mere commoner having a dig.

The story opens in London 1940 as a young girl at a tall window watches bombs fall over the city. This turns out to be the 10-year-old Princess Margaret (“she hated being 10”), at home in Buckingham Palace. Such is the danger from the blitz that Margaret’s parents decide that she and her 14-year-old sister, Elizabeth, should be secretly packed off to a safe house till the coast is clear. Some bright spark chooses neutral Ireland as their bolt-hole, specifically Clonmillis House in darkest Tipperary, home of their distant relative the Duke of Edenmore.

Chief operative in the plan is languid patrician Richard Lascelles, a British diplomat who negotiates a quid pro quo with the Irish government: if they agree to shelter the two princesses, Whitehall will sanction shipments of much-needed coal to Ireland.

Bearing the assumed names of Mary and Ellen, the royal sisters are placed in the care of two very different protectors. One of them is Celia Nashe, a Roedean-educated MI5 agent who views this hush-hush assignment as pretty “rum”. Her ambitions to be tested in the field aren’t going to be satisfied by such a posting: “The Maginot Line was a long way from Tipperary.” The other is Detective Garda Strafford, son of the Anglo-Irish ascendancy, a detached, unflappable fellow with a Waugh-like sense of the absurd.

Both are anomalies in their professions – Celia a woman in a man’s world, Strafford a Protestant in a Catholic one – which might, you suppose, create an outsiders’ bond, marooned together in “Ballymacbackward”. And yet mutual suspicion hardens into an estrangement between them, just as it colours the wider story.

Benighted Ireland, where DH Lawrence’s Women in Love is a banned book, is so riven with historical resentments and grievances that there is no telling where loyalties might lie. A Major de Valera, son of Éamon, features ambiguously in the supporting cast. All Nashe and Strafford know is that the true identity of their charges must be kept close: if the IRA get wind of their presence, for example, a kidnapping could have a disastrous effect on British morale.

Banville (or rather Black) is good on the contrast between the adults and the royal children, with their “grave, antique look” and haughty self-possession. You sense he has been a devotee of the Netflix series The Crown and enjoys the freedom of imagining the private feelings beneath the public front.

Related: John Banville: ‘The Catechism had all the answers. If only it were all true’

“Mary” in particular is well drawn – inquisitive, precocious, “a practised listener at keyholes and outside bedroom doors”. She fancies herself in love with the estate’s saturnine gamekeeper, whose mother was allegedly murdered by the Black and Tans when he was an infant: “Maybe a tragedy like that stayed with you all your life.” (It has to be said that that’s remarkable empathy for a 10-year-old, and even more so for a 10-year-old who would grow up to be Princess Margaret.) It will also be her decisive intervention that lends the plot its small twist. In describing Clonmillis Hall – drab, cold, unfriendly, “a mausoleum” – Black may also have in mind the decrepit hotel at the centre of JG Farrell’s Troubles, with its lowering atmosphere of dread.

The Secret Guests is a nicely worked conceit without being a scintillating one. It takes a while to get going, focused upon the deep crosscurrents of mistrust among its cast and the somewhat incongruous presence of its high-born star-turns.

When the plot does finally ignite, the set pieces that have been carefully prepared are rather hurried through. This saddles the book with a strange and ungainly rhythm. That might not matter: given the fathomless appetite for gossip about the House of Windsor, this little jeu d’esprit on the early life of the royals could find an enthusiastic readership.

•Anthony Quinn’s Our Friends in Berlin is published by Vintage. The Secret Guests by BW Black is published by Penguin (RRP £8.99). To order a copy go to guardianbookshop.com. Free UK p&p over £15.