Prince Philip was an integral part of the Royal Family for decades, until his death on April 9, 2021. But according to one royal biographer, Queen Elizabeth's husband didn't have much affection for one particular family member.
During an appearance on the podcast, "The Firm: Blood, Lies, and Royal Succession," royal expert and biographer Jane Dismore shared (via Hello! magazine), "[Philip] didn't like Fergie [Sarah Ferguson]—she knew that she wasn't welcome when Prince Philip was around." Dismore further explained, "She's the one person that Prince Philip would not have anything to do with."
According to Dismore, many royal staff members shared Prince Philip's view of Andrew Mountbatten-Windsor's then-wife.
"Ferguson's idea of being royal was best summed up by one of the courtiers who said, 'Vulgar, vulgar, vulgar,'" Dismore explained. "She hadn't an idea of what being royal really meant. It wasn't just the awful lapses of judgment. It was an attitude to royal life."

This isn't the first time Prince Philip's alleged hatred of Ferguson has been raised.
When Ferguson's daughter, Princess Eugenie, got married in October 2018, there were rumors that Prince Philip might skip the nuptials in order to avoid his ex-daughter-in-law.
"[H]e hates Fergie so much he can't stand to be in the same place as her," a source told the Express at the time.
While Prince Philip did attend granddaughter Eugenie's royal wedding to Jack Brooksbank, he allegedly avoided Ferguson for the duration of the event.

Basically, it's pretty safe to say there was no love lost between Prince Philip and his son Andrew's ex-wife.