The first two series of Black Mirror were originally broadcast in the UK on Channel 4. The anthology premiered there in December 2011, beginning with “The National Anthem,” and its second series followed in February 2013.
Channel 4 commissioned the programme and carried its first six episodes, three in each of the first two series. The network also aired the 2014 special “White Christmas,” which became the final Black Mirror instalment made for Channel 4 before the show’s international expansion.
A common mix-up comes from Black Mirror’s later association with Netflix. Netflix acquired the programme after Channel 4, commissioning the episodes that became series three and distributing them internationally from 2016. In the UK, however, Channel 4 remains the original broadcaster of the first two series.
The distinction is between original broadcast and later streaming availability: Netflix eventually offered the early episodes in several markets, but it did not originally broadcast those first two UK series.