The claim was made by Robert Lacey in his new book, ‘Battle of Brothers’, which deals with the deteriorating relationship between Prince William and Prince Harry over the past few years. Kate and William met in 2001 during their first year at St. Andrew’s University.
They began dating two years later and lived together along with two other students.
According to Mr Lacey Kate was determined to make the relationship work, but had a backup plan in case it didn’t.
He wrote: “While Kate’s medium-to-long-term objective was quite simple – to lead William in handcuffs to the altar – for the time being, she had to devise her own independent career path as camouflage.
“In neither respect would it help Ms Middleton to appear the slightest bit needy – and of course there was the ultimate unthinkable possibility that she might end up getting dumped!”
After graduating Kate joined Jigsaw, a British fashion label.
In 2007, whilst working there, she did briefly split from William.
According to Mr Lacey William “dumped Kate over the phone” after calling her at work.
He said: “Kate excused herself from a meeting at Jigsaw, the fashion store with which she’d recently started working, to take a call from William in a room out of earshot of the other buyers.
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Kate revealed she had found it difficult not to be “consumed” by the relationship.
She added: “At the time, I wasn’t very happy about it but actually it made me a stronger person.
William said: “We were sort of both finding ourselves as such and being different characters and stuff, it was very much trying to find our own way and we were growing up.”
William and Kate’s wedding, at Westminster Abbey on April 29 2011, attracted an audience of hundreds of millions across the world.
In the UK TV coverage attracted a peak of 26.3 million viewers, with at least 36.7 million viewing at least some of the ceremony.
Kate and William have three children, Princes George and Louis and Princess Charlotte, who were born between 2013 and 2018.
The family spent the first COVID-19 lockdown at their Anmer Hall country home in Norfolk.
Both the Duke and Duchess continued conducting royal engagements, initially via video app and later in person again.
Prince Harry and Meghan Markle moved to California shortly before the state went into a coronavirus inspired lockdown.
The couple had stepped down from senior royal duties at the end of March.