As part of the reigning monarch's duties, he or she gets to award honorary titles to people who serve the British Commonwealth in some way. This was once Queen Elizabeth's job, but now it has been passed down to King Charles. People can receive the awards for everything from musical contributions (Fun fact: The Beatles got MBEs in the 1960s) to just being really good to the royal family. For example, Kate Middleton's OB-GYN got knighted after he delayed his retirement to help with Prince George's birth. (Prince William did the knighting honors on that one.)
But not everyone who gets a title gets to keep it. Over the years, extreme circumstances have led to some people being stripped of their royal titles, whether in Britain or elsewhere. And it's not just the commoners who can lose their royally appointed titles.
Members of the royal family have also had their special titles taken away from time to time. The Guardian reported that it's "extremely rare" for honorary titles to be withdrawn, but it's happened a fair amount over the years.
Basically, the monarchy giveth, and the monarchy taketh away …
Harvey Weinstein

In 2004, film producer Harvey Weinstein received the second-highest honorary title the British monarch gives out: the Commander of the Most Excellent Order of the British Empire, or CBE. He got the award for his contributions to British film, but after his rape conviction in 2020, he was stripped of the title, per the Telegraph.
Benito Mussolini

Benito Mussolini, former Italian prime minister and founder of the National Fascist Party, had previously been named Knight Grand Cross of the Order of the Bath by King George V in 1923. But as the Guardian noted, he lost the honor when Italy teamed up with Germany during World War II and declared war on the UK.
Prince Philip
The late Prince Philip sacrificed a lot to marry Queen Elizabeth. By joining the British monarchy, he lost his birthright to the Greek throne, as well as his royal title Prince Philip of Greece and Denmark. The Queen's father tried to make him feel better by naming him the Duke of Edinburgh, and in 1957 the Queen gave him a new honorary prince title to replace his old one.
Anthony Blunt

The Queen's art curator, Anthony Blunt, was given the highest honor by her majesty: a knighthood. Elizabeth stripped him of that title, however, after he was outed as having been a Soviet spy during World War II. This ended up becoming a storyline on the Netflix series The Crown.
Kim Philby

Kim Philby was a British intelligence officer for MI6, which made his value as a spy for the Soviets extremely high. But before his treacherous ways were discovered, he was awarded the OBE, or Officer of the Most Excellent Order of the British Empire, in 1946 for his intelligence work. After his double agent status was made clear, however, he was stripped of his title.
Several Swedish Royals
Sweden's King Carl XVI Gustaf got rid of the His and Her Royal Highness titles for all five of his grandchildren in 2019. According to People, the decision was made to allow the children to lead more private lives and not have to be working royals.
"I think it's good that our children are now getting a greater opportunity to shape their own lives as private individuals in the future," Princess Madeleine wrote of the decision. Prince Carl Philip added, "Our children no longer hold the Royal Highness position. We see this as positive as Alexander and Gabriel will have freer choices in life."
Basically, the Swedish royal grandchildren got what Prince Harry had to force his way into.
Prince Harry & Meghan Markle
After their decision in 2020 to leave royal life behind, Prince Harry and Meghan Markle had to relinquish their His and Her Royal Highness titles. They weren't officially stripped of them, but because they're no longer working royals, they're not allowed to go by HRH. Harry can still go by Prince Harry, however, and they both got to keep their Duke and Duchess of Sussex titles. Because they're not royals anymore, they also can't go by Sussex Royal, which is why they had to give up their Sussex Royal Instagram page.
Harry's Military Titles

As a senior royal, Harry had been granted several honorary military titles, which he was stripped of after his exit from royal life.
The 2020 tell-all book Finding Freedom alleged that losing the titles was "demoralizing" for Harry. Among the titles taken away were Captain General of the Royal Marines, Honorary Air Force Commandant of the Royal Air Force Base Honington, and Honorary Commodore-in-Chief of the Royal Navy's Small Ships and Diving Operations.
Princess Diana

When Princess Diana and King Charles (then a prince) divorced in 1996, she lost the title of Her Royal Highness, ranking her lower than every other royal. Technically, protocol dictated that she needed to curtsy to even her own sons, because they retained the HRH status. According to Reader's Digest, the Queen didn't demand that Diana be stripped of the title — Charles did. Petty much? Little Prince William reportedly promised to give it back to Diana one day when he was in charge, although he never got that chance.
Ernest Brooks
War photographer Ernest Brooks had been awarded the OBE and British Empire Medal, according to Express. But the royal family quickly took those honors away when Ernest released an image of the future King Edward VIII in a kimono and wig ahead of a theater performance. The royals are all about controlling their image, and Ernest was apparently a threat to that.
Robert Mugabe
Robert Mugabe, former prime minister and president of Zimbabwe, was knighted in 1994, but the honor was rescinded in 2008 because of his role in "political violence," per the CBC. A statement from Britain's Foreign Office said Queen Elizabeth stripped him of his honor "as a mark of revulsion at the abuse of human rights and abject disregard for the democratic process in Zimbabwe over which President Mugabe has presided."
Naseem Hamed

Professional boxer Naseem Hamed's MBE, or Member of the Most Excellent Order of the British Empire, was taken away after he caused a devastating car crash as a result of him driving 90 miles per hour. He fled the scene but was later arrested and sent to prison for four months. A palace representative said MBE titles can be rescinded if a person has "done something which shows they shouldn't have received an honor."
Roger Casement

British diplomat Roger Casement was knighted in 1911 for his work as a human rights activist, but that title was taken away a few years later when it was discovered that he'd been conspiring with the Germans to lead an Irish uprising. In addition to just losing his "sir" title, he was also executed.
James Crosby
Banking boss James Crosby was a large part of the 2008 banking crisis in the UK, according to the Guardian. Because of his role in his industry's collapse, he asked for his knighthood to be revoked as part of his punishment. He likely knew it was coming anyway, and the Queen gladly agreed.
Jean Else

Headmistress Jean Else was granted the Dame of the British Empire, or DBE, award in 2001 for her services to British education. But she became the first woman to lose that title in 2011, when it was discovered she was using nepotism to hire her friends and family at work. She also used school money to pay for a celebration after she won the DBE.
Rolf Harris

Australian entertainer and artist Rolf Harris was given the MBE and OBE before eventually receiving a CBE for painting the Queen's 80th birthday portrait. His titles were all rescinded after he was convicted on 12 counts of indecent assault on underage girls.
Prince Charles Edward

Queen Victoria's grandson Prince Charles Edward picked the wrong side in World War I and paid dearly for it. According to Express, he supported the Germans in the war effort, causing uproar in England. When the war ended, King George V stripped him of all his titles, leaving him to live as a commoner rather than a prince. That did nothing to stop him from again backing Germany in World War II.
Vicky Pryce

Economist Vicky Pryce won the coveted Companion of the Order of the Bath, but the Queen ordered it be taken away in 2013. The decision came after it was discovered that Vicky had been taking speeding penalties on behalf of her husband so he'd still be allowed to drive. Vicky served eight months in jail and lost her title.
Lester Piggott

Famed horse jockey Lester Piggott was awarded the OBE in recognition of his stellar horse racing. (He won the Epsom Derby nine times, per the Guardian.) But he lost that same honor after he was convicted of tax evasion. Officials may say it's rare for people to lose their titles, but it sure seems to happen a lot.
Stuart Hall

BBC broadcaster Stuart Hall fell from grace after he was convicted of 14 counts of sexual assault against underage girls. He was sent to prison, and the Queen quickly took away his OBE. Per the BBC, Queen Elizabeth "canceled and annulled" his honor and "erased" his name from the OBE registry. She didn't mess around.
Prince Andrew
One of the most recent strippings of royal titles happened to Prince Andrew in January 2022, after he was publicly disgraced for his involvement in the Jeffrey Epstein scandal. Although he did retain the title of prince, Andrew lost everything else — including his military affiliations and royal patronages.
Prince Joachim of Denmark's Children

Following a decision that was viewed as rather controversial by Queen Margrethe II of Denmark, as of January 1, 2023, all four of Prince Joachim's children were stripped of their titles. Margrethe said it was so they could more easily lead normal, non-royal lives, and although they are now known as Counts and Countesses of Monpezat, they can no longer be referred to as prince, princess, or HRH.