Seldom had anyone seen Britain's Queen so cross. She had summoned her cousin, Prince Michael of Kent, to Buckingham Palace one wet afternoon in 1977 and told him in no uncertain terms that he shouldn't marry the woman he loved.
It would, said the Queen, cause a scandal that would rock the royal family. For Michael was planning to marry Marie Christine von Reibnitz. Not only was she foreign, divorced and a Roman Catholic, but her father had briefly been in Germany's party.
At 32, Marie Christine was a former German ski champion with a reputation for saying what she thought. Even before her marriage she had been nick-named "Princess Pushy" by the press, and the Queen took a dim view of that, too.
The interview with Prince Michael came to an abrupt end when the Queen said: "I don't want that woman's name mentioned in front of me again" and Michael angrily left the room.
"It made him all the more determined to marry the woman he loved," a friend remembers. "Now nearly 40 years later he knows he made the right decision. Despite some ups and downs they are probably the happiest of all the royal couples."
The biggest sacrifice Michael made was to give up his claim to the throne — he was 16th in line — and he did so gladly. "Unless a bomb fell on Buckingham Palace my accession was pretty academic," he said.
Marie Christine is the daughter of a German baron and a Hungarian heiress. She went to an exclusive Catholic boarding school where she was nicknamed "The Baroness".
Even then she was a striking figure, tall and statuesque with long blonde hair. Said one of her schoolmates: "She had charm and style way beyond her years. When she walked into a party everything would stop."
In England in the early 1970s, she met and married an Old Etonian, Tom Troubridge whose old friend, Prince William of Gloucester, invited the couple to stay at his country home, Barnwell Manor.
It was there that Marie Christine was introduced to the bachelor Prince Michael. "I thought he was the funniest man I had ever met," she said later.
Friends remembered that the couple were instantly attracted to each other. Said one: "The Troubridge marriage was in trouble and meeting Michael probably pushed it over the edge although they only started seeing each other after the divorce.
"Marie Christine admitted that the moment she saw Prince Michael she was swept off her feet."
From the moment they were seen out together, the palace closed ranks to wreck the romance, but they had reckoned without the steely determination of Marie Christine and her prince.
As soon as the divorce from Tom Troubridge was absolute, they were married in a Vienna register office in 1978 with no other members of the royal family present.
Later, after five years of petitioning the Vatican, the princess's earlier marriage was annulled and the couple finally had their wedding blessed in church.
It wasn't long before Marie Christine got her "Princess Pushy" tag and became legendary for saying what she shouldn't. She was constantly embroiled in turmoil and controversy.
Only weeks after joining the royal family she described the Duchess of York as "the Coronation Street princess," said Princess Caroline of Monaco was "just the daughter of some movie star" and admitted that "Michael and I will go anywhere for a hot meal."
In one tactless and outspoken interview she declared: "I've got a better background than anyone who has married into the royal family, except Prince Philip. It's rotten being a princess — there's total lack of privacy."
The couple were given a grace and favour home on the royal estate but it was made clear they weren't welcome at Buckingham Palace.
One royal insider reported: "Both the Queen Mother and Princess Margaret would do anything to avoid Princess Michael."
And when Margaret's son, Viscount Linley was asked what he would give his worst enemy for Christmas he replied: "Dinner with Princess Michael!"
But despite being given the royal brush-off, the prince and princess have a wide circle of friends, many in show-business, and with their children Frederick and Gabriella are a close-knit and happy family.
The royal rift means that Prince Michael gets no income from the Queen. He had a long career in the army, retiring as a major.
Since then he has worked in his own consultancy business and has presented TV documentaries.
He is also a qualified Russian interpreter. His wife has written two best-selling books and has done promotional work in the fashion industry.
Recently looking back on over 36 years of marriage, Marie Christine said: "We've had our problems but I don't regret a day of it. And proving the doubters were wrong never ceases to make me smile."