Rigby & Peller has been held a royal warrant from the monarchy since 1960, well before Kenton and her husband bought the company for 20,000 pounds in 1982.
The working relationship relationship between June Kenton, the woman said to be the "driving force" behind the brand, and the Queen reportedly came to an end in 2016, not long after after Kenton, 82, wrote a tell-all book "Storm In A D Cup".
"The royal household warrants committee has chose to cancel the royal warrant granted to Rigby & Peller and Mrs June Kenton", the brand said in a statement.
A spokesperson for Buckingham Palace said: "In respect of royal warrants, we never comment on individual companies".
Yesterday Russell Tanguay, director of warrants at the Royal Warrant Holders Association, confirmed that Rigby & Peller, whose flagship store is near Harrods in Knightsbridge, had lost its warrant.
The Royal Warrant Holders Association diligently catalogs these esteemed businesses: Burberry, for example, serves as the Queen's official weatherproofers, while Hunter supplies waterproof footwear (aka Wellies).
A British bra-fitter was stripped of its royal warrant after the former owner released a book disclosing details of the company's private fittings at Buckingham Palace.
Rigby & Peller is a London-based luxury underwear brand.
"I'm very sad Buckingham Palace took exception to the story - it's a kind and gentle story about what went on in my life", said Keller, according to the BBC.
"I only ever said I went there, not what happened".
"It is very sad for me that they didn't like [the book] and I'm finding that very hard to accept".
The author and bra-fitter wrote: "I never met William or Harry - though (Princess Diana) was always talking about them". She was surprised at the response as, in her mind, "The book doesn't contain anything naughty". "I'm proud of my life and what I've achieved and I simply want to share that".
But the BBC understood that Prince Philip was angered by allegations made by owner Mohamed al Fayed accusing the Duke of masterminding the 1997 auto crash in Paris that killed Diana, Princess of Wales and his son Dodi.