From The TV IV
BBC Two is a channel of the BBC. It was the third television network in the United Kingdom, the first to be available only on the UHF band, and the first to broadcast in colour. Its approach has traditionally been more upmarket than its sister channel BBC One.
BBC2 was scheduled to be launched at 7:20PM on April 20, 1964. However, at about 6:45PM a power failure at the Battersea Power Station resulted in the BBC Television Centre losing all power. BBC1 was able to continue broadcasting, but all attempts to show the scheduled programming on BBC2 failed. BBC2's launch was postponed and its programming finally began at 11AM on April 21, 1964. In reference to the power loss, the BBC2 transmission opened with a shot of a lit candle which was then blown out by presenter Denis Tuohy.
During the BBC2's first thirty years the channel developed a reputation of screening highly praised drama series and documentaries. More recently, however, critics have stated the channel has moved to becoming more orientated towards showing "mainstream" shows.