<P> The episode was shot in Iceland and includes scenes filmed in the Harpa concert hall . Brooker had originally called out for filming in Scotland in his script, but Netflix suggested Iceland as a "more stunning backdrop", according to Brooker . During filming, Iceland had its largest snowfall in forty years, which required them to add one line of dialogue to comment on the change of weather to account for the sudden snow accumulation . </P> <P> In May 2017, a Reddit post unofficially announced the names and directors of the six episodes in series 4 of Black Mirror . The first trailer for the series was released by Netflix on 25 August 2017, and contained the six episode titles . </P> <P> Beginning on 24 November 2017, Netflix published a series of posters and trailers for the fourth series of the show, referred to as the "13 Days of Black Mirror". On 6 December, Netflix published a trailer featuring an amalgamation of scenes from the fourth series, which announced that the series would be released on 29 December . </P> <P> The episode received mixed reviews . The cinematography of the Icelandic landscape was widely praised, along with Riseborough's and Sawar's performances . Two critics criticised the violence and described it as unnecessarily bleak . </P>

Where was season 4 episode 4 of black mirror filmed