	As the format of "Inside No. 9" requires new characters each week, the writers were able to attract actors who may have been unwilling to commit to an entire series. "The Harrowing" starred Aimee-Ffion Edwards as Katy, Helen McCrory as Tabitha, Shearsmith as Hector, Poppy Rush as Shell and Sean Buckley as Andras. "The Harrowing" was the only episode in the series in which Pemberton did not star; Shearsmith played a character in all but "Last Gasp". Comedy critic Bruce Dessau noted that Shearsmith's role was actually relatively minor, saying that the house was the real star.