Speaking to The Telegraph after Sir Keir was taken by his entourage, Paul Stoner explained why he had made the unusual offer.
The 60-year-old said: “I asked him if he wanted an apple and when he said‘ yes ’I gave him a lemon because I think it’s a bit of a joke.
“If you say lemon to someone, you think it’s a little idiotic, a little sour.
“He didn’t even realize it wasn’t an apple. He just looked confused and said “thank you.”