He twice attended the South of England Showground in Ardingly.
The last occasion was in 2002 when he accompanied the Queen in a carriage around the showground.
Carole Hayward, chairman of the education committee of the South of England Agricultural Society, was introduced to the Queen while Prince Philip chatted informally to others.
“They all had a jolly time,” said Carole, who is also a vice chairman and trustee of the agricultural society, as well as a Deputy Lieutenant of West Sussex. “I didn’t get to speak to him.”
The Duke of Edinburgh was president of the society back in 1979 but was unable to attend the show in June that year.
Instead, a dinner was later organised which the Duke attended along with society vice patrons and council members.
Carole said that the society chairman at the time - Jim Green - reported that the occasion was “very pleasant and informal and the Duke spoke to every guest.”