From TARDIS Index File, the free Doctor Who reference.

This article is written from the Real World point of view.

This article is about the real-world British Broadcasting Corporation channel. For the network as featured within the fictional Doctor Who universe, see BBC3.

BBC Three is a digital only channel in the United Kingdom. The channel launched in 2003, but its existence was in fact predicted decades earlier, in the 1972 Doctor Who story The Dæmons, which featured a fictional BBC3 network.

Episodes of the BBC Wales produced Doctor Who are also repeated on BBC Three with an optional commentary availible on some services the Sunday after their Saturday transmission.

Torchwood was the first science fiction programme commissioned to broadcast on BBC Three.

Wikipedia has a more detailed and comprehensive article on

BBC Three