Sarah Ferguson's new children's book has been withdrawn from sale

The publisher, New Frontier Publishing, has not responded to the BBC's requests for comment.

Last month, Waterstones bookstores told BBC News that the publication date had "moved" and that they did not have a new publication date.

Neill Denny, from the book trade news website Book Brunch, told the BBC: "It makes total sense commercially.

"You have to imagine it's to do with the current controversies. It's not the right time to release a book by Sarah Ferguson. It's not the sort of book that's going to age, and you're not risking a lot of money by holding it back."

Meanwhile, Sarah lost her Duchess of York title and much of her earning power after becoming embroiled in the scandal surrounding convicted sex offender Jeffrey Epstein.

In an email written to Epstein in 2011, which was made public earlier this year, Sarah issued an apology for distancing herself from him after his 2008 conviction for procuring a minor for sex.

A source close to her said the email had been written "in panic" and without legal advice, explaining: "She feared Epstein would sue her for libel. She hadn't committed any crimes - she was just hapless. If there was a Second World War bomb in Piccadilly, Sarah would step on it and set it off."

Socialite and party planner Liz Brewer told The i newspaper that Sarah had always been "very personable" but admitted she was currently unwelcome at high-society gatherings.

She said: "People, unfortunately, are not brave enough to make their own minds up. She's in a very difficult position."

Sarah was also been dropped by several charities and media outlets.

Ferguson is said to be considering options to restore her finances, including a potential interview with Oprah Winfrey, who has previously hosted her twice - in 1996 following her separation from Andrew and in 2010 after a News of the World undercover sting.

The interview could reportedly fetch up to $1 million.

Another possible project is a memoir revealing her experience of royal life, which could also attract a six-figure payday.