http://www.bbc.co.uk/historyofthebbc At 3pm on 2 November 1936 the BBC began the world's first regular hi-definition television service, from specially constructed studios at Alexandra Palace in North London. As part of this, two different technical systems were being tested on alternate weeks for six months: John Logie Baird's mechanical system producing pictures of 240 lines, and the EMI-Marconi electronic system, which produced images of 405 lines. On the toss of a coin, Baird's system inaugurated the service, followed by EMI-Marconi's. The latter was to prove the winning system.
The formal opening ceremony was followed by a Movietone newsreel and then a variety show, featuring Adele Dixon and the BBC Television Orchestra. A short documentary, Television Comes to London, revealed the preparations leading up to the launch. In all, the service was on the air for two hours on its first day.
Watch a selection of clips from programmes which all came from Alexandra Palace, when the BBC was there, 1936-1981.