Former Harrods owner Mohamed al Fayed has revealed he had the store's royal warrants taken down and burned.
The Egyptian businessman said the endorsements - from the Queen, Duke of Edinburgh, the late Queen Mother and the Prince of Wales - were a "curse" on the famous shop.
In a letter to The Sunday Telegraph, he said of the warrants: "I ordered their removal. Later, I had them burned. They were a curse and business tripled following their removal."
Mr al Fayed has attacked the Royal Family on several occasions since the deaths of his son Dodi and Diana, Princess of Wales in a Paris car crash in 1997.
In a 1999 court case he accused the Duke of Edinburgh of "masterminding" the deaths, also describing the royals as "that Dracula family" during the 2008 Diana inquest.
The royal warrants were removed from Harrods in 2000.
In his letter, Mr al Fayed, who sold the Knightsbridge store for £1.5 billion to the Qatari royal family, also called for the new owners to keep two memorials to his son and the late Princess.
He said of one: "Unless and until this country gives the Princess the thanks and devotion she deserves in the form of a fitting public memorial, this statue, Innocent Victims, should remain to remind the world of what was lost when two young people were on the brink of happiness together, were killed."
The billionaire added: "It is the only memorial to the Princess in the country, if one discounts the misconceived municipal waterworks in Hyde Park that every year causes casualties among the children who slip over when paddling in it."