 This is the first "Doctor Who" episode to be shot at the new dedicated Upper Boat studios in Pontypridd; the TARDIS set had previously been housed in former warehouse space in Newport.Although the episode was set during Christmas, filming took place in July, where temperatures reached 30C in Cardiff during filming.Night filming of scenes involving gunfire, explosions and a tank, as well as those on "Oxford Street", were filmed on St. Mary Street outside Howell's Department Store in Cardiff City Centre; Cardiff Castle is visible behind the tank in some shots.