At the 100-year celebration of the Women's Institute in 2015, Queen Elizabeth cut the ceremonial first slice of cake — or at least, she tried to.
"If you look closely, you can see the knife stuck in the cake," Jackson previously told Insider. "It's a great example of when things don't always go to plan, it often makes the best photographs. Everyone bursts into laughter, and it's suddenly a relaxed moment."
Jackson said Princess Anne finally managed to dislodge the knife.
"It's one of those things where you might not know exactly what's going on if you look at this picture," he said. "But if you look at the detail a little bit closely, you can probably figure it out."