For Sarah ‘Fergie’ Ferguson, the Duchess of York, it must be the best and worst of times. Even as her former husband Prince Andrew sinks ever deeper into the reputational mire brought about by the Jeffrey Epstein scandal, she can console herself with the recent news that her Mills & Boon novel, the absurdly named Her Heart for a Compass, has become a bestseller. Granted, it may have sold just over a thousand copies in the past week, but, in the quiet month of August, this is enough to add ‘top novelist’ to Fergie’s many other accomplishments.

The duchess was suitably gracious in celebration: ‘I am absolutely delighted to have embarked on a new career as a novelist at the age of 61 and to be rewarded with a top 10 bestseller. It really is a dream come true and I’d like to thank everyone who has been buying the book so far.’ She also made the autobiographical overtones explicit to her readers and any passing civilians: ‘I hope they are enjoying the exploits of my headstrong, redheaded heroine Lady Margaret and are spotting the parallels between my own life and hers.’

It is possible that Fergie’s rolling acres of reviews and interviews have given Her Heart for a Compass a much wider profile than Mills & Boon novels typically receive. Likewise, assistance from her co-writer, the veteran romance writer Marguerite Kaye, ensured a basic level of competence which may have been excitingly absent had the Duchess dispensed with the services of a ghost.

Nonetheless, it would be cruel to deny Fergie her moment of triumph, even if comes with the harrowing news that she is now co-writing another novel. She claims that she is ‘ready to embrace the opportunities and challenges of writing adult fiction’ and threatens to ‘build on what I have learned when writing Her Heart for a Compass’.

She has, of course, written children’s books before, most famously Budgie: The Little Helicopter, but this is her first foray into adult fiction. In this, she differs from the other literarily inclined members of the British royal family, the Duke and Duchess of Sussex. Meghan Markle recently published her first children’s picture book, The Bench, which was greeted with a mixture of dismay and appalled fascination. The critic Andrew O’Hagan wrote in the LRB that Markle ‘has written a children’s book which is not for children at all, and possibly not for anyone’ ­– and that was one of the kinder reviews. Meanwhile, her husband — not to be outdone — is preparing to publish his autobiography next year, apparently entitled Strap In. He has hired the ghostwriter J.R. Moehringer, who was responsible for Andre Agassi’s bestselling memoir Open. There is the tacit promise of yet more damaging and embarrassing revelations about his long-suffering family.

Aunt Fergie’s literary ambitions seem relatively modest in comparison. Having already published two volumes of memoir — 1996’s My Story and 2011’s Finding Sarah — she may now be content with writing undemanding fiction in which the autobiographical overtones are present but not over-emphasized. But should the house of cards come crashing down around her former husband Prince Andrew, and he find himself facing serious legal difficulties, the Duchess of York will be faced with a dilemma. Does she continue her long-held policy of loyalty and silence towards Andrew? Or should she accept the entreaties of publishers and write a tell-all book? If she chooses the latter, she can expect to return to the bestseller charts once again — and this time in far greater numbers. Ma’am, your public awaits.