The Queen's 1957 Christmas Broadcast was an historic event, as it was the first to be televised. It was also the 25th anniversary of the first Christmas Broadcast on the radio. The broadcast was made live from the Long Library at Sandringham, Norfolk.

After a scathing magazine article criticizes the queen’s relatability and speech-making style, she explores new ways to better connect with the British people. A few months later, a nervous Elizabeth is in front of the camera warmly addressing her subjects during her first televised Royal Christmas Message, beginning a tradition she would continue to observe for the next 64 years. 

Here you can find the link for the official speech.