Watch: Security conscious Queen Elizabeth asks if automatic checkouts can be 'diddled'

Britain's Queen Elizabeth II got a lesson in shopping at the self-service counter when she visited UK supermarket Sainsbury's on Wednesday. The inquisitive monarch asked if customers could use the system, which functions without a cashier, to steal products. "You can't diddle it, you can't cheat?" Her Majesty said. She paid the visit to the pop-up replica of the original Sainsbury's shop in London to celebrate the 150th anniversary of the British high street chain. The 93-year-old was greeted by Lord John Sainsbury, the great-grandson of the supermarket chain's founder John James Sainsbury. The Queen was shown how shoppers used self-service tills and paid using their mobile phones, although she did not try it out herself. She also met members of staff and cut a commemorative birthday cake.