It started with an unhappy customer and, thanks to the quick thinking of chef and restaurant owner Ali Ahmed Aslam, ended with a dish that has become a real British classic: the chicken tikka masala. Ali recently passed away, aged 77, and will be remembered as the inventor of one of the UK's favourite dishes. He's pictured here in his restaurant, Glasgow’s Shish Mahal, which has become a pilgrimage spot for fans of the dish. Read on for more on how he invented it.