When he heard the news that George VI had died, the Duke of Edinburgh looked as if half the world had been dropped on him, his close aide once said.
Philip had been expected to take a large share of royal engagements as the King’s health grew worse.
He and Princess Elizabeth had made their first major tour together to Canada and the United States in October and November 1951, after which the duke was made a Privy Counsellor.
Yet on February 6, 1952, both their lives changed irrevocably.
Elizabeth and Philip were on a tour of Kenya when a message was given to the duke that the King was dead.
It was the duke who broke the news to his wife, the new Queen, while they were alone.
They had been staying at Sagana Lodge, which had been given to them as a wedding present by the people of Kenya.
It was 2.45pm in Kenya and Elizabeth had been resting after spending the night at the Treetops Hotel, in Aberdare Forest, watching big game.
Just hours later they were on their way back home to the UK.
Philip’s equerry and friend Mike Parker had passed on the news of the King’s death.
“He looked as if you’d dropped half the world on him,” Parker later said. “I never felt so sorry for anyone in all my life.”
Both men knew that everything had changed and life would never be the same again.
Parker and Martin Charteris, Elizabeth’s private secretary, packed up, worked out timetables, sent a flood of signals, organised a plane at Entebbe, another from Mombasa to get there, and timed a London airport arrival for 4pm the following day.
With the King’s health failing when they had left home, a Royal Standard had been stowed in the baggage.
Elizabeth’s mourning clothes were now taken out and prepared for her to wear.
The 4,000-mile flight home was met by the Prime Minister Winston Churchill, with Opposition Leader Clement Attlee and the Duke of Gloucester.
Elizabeth, just 25 and dressed in black, emerged from the plane, returning as the country’s new Queen.
But Philip knew his dramatically-altered place.
He waited for his wife to set foot on British soil before he made his own way down the steps to the tarmac.
It was the beginning of a long and now much-changed partnership.