Mr Griffin recalled a time when the monarch was approached by a group of American tourists while on a walk near the Balmoral Estate in Aberdeenshire at a recent talk, according to The Times.
The group asked the Queen, who was wearing a headscarf and tweed coat, if she lived in the area, to which she responded simply by saying she had a house close-by.
“Have you ever met the Queen?” they asked.
“No,” she apparently replied, before pointing at the policeman and adding: “But he has.” The group were still none the wiser and left without realising whose company they had just shared.
Balmoral Castle and Estate was purchased by Queen Victoria and passed down to members of the Royal family. The grounds are opened to the public from May to July each year.
A spokesperson for Kensington Palace told the Independent Mr Griffin worked closely with the Queen as a protection officer for over 30 years.
By Heather Saul