What year, did the Queen of the United Kingdom, Elizabeth II, first appear live for an official event on British television?

It is held by some critics that Queen Elizabeth II's 1953 Coronation is the day that changed live British television. Some people believe that the coronation was the moment when television was instantly transformed from a primitive, minority activity into a sophisticated mass medium. A few have even suggested that without the Queen's coronation, television as a medium would never have taken off. But, this idea of the coronation as a watershed for British TV is unconvincing. By 1953, television in Britain was nearly 30 years old, had accumulated thousands of broadcasting hours and had been seen by millions. Purportedly, the number of new licences rose from 400,000 in 1950 to 700,000 in 1951 and 1952 and 1,100,000 in 1953, suggesting that the sales hike for the coronation was part of a steady, inexorable rise, not something sparked by one event. The coronation just gave television a very helpful nudge, that is all.