The book, The Other Side of the Coin: the Queen, the Dresser and the Wardrobe by Angela Kelly, recounts the amusing response the Queen had when a guest tripped over one of her corgis when visiting Buckingham Palace...
In June 2000, Kelly recounts, Mr Harry Collins from G. Collins & Sons visited the palace to present the Queen with a brooch he had made for her 100th birthday.
"Having read somewhere that where possible, one should not turn their back on The Queen, he proceeded to walk away backwards,’ Kelly wrote.
"Unfortunately, Mr Collins failed to notice Linnet, one of Her Majesty’s corgis, lying on the floor behind him. He tripped over Linnet and ended up next to the dog, lying spread-eagled on the carpet. Terrified that he’d hurt one of The Queen’s dogs, Harry frantically rubbed Linnet’s chest, apologising profusely."
But, the Queen wasn't bothered by the incident and instead gave a very light-hearted response.
"Her Majesty reassured Mr Collins and told him not to worry: it was not his fault as the corgis had a terrible habit of lying in the most awkward places."