Laurence Cendrowicz/ITV Studios for MASTERPIECE
And the miniseries, which premieres Sunday at 9 p.m. on Channel 2, contains a number of irresistible secondary characters — none, perhaps, as indelible as the Dowager Countess played by Maggie Smith on “Downton Abbey,” but that would be an impossible standard. There is Ellen Love, a showgirl who becomes the face of Selfridge’s store. Played by Zoë Tapper, she is a very watchable blend of ambition and two-bit glamour. And there is Lady Mae Loxley, played with calm ferocity by Katherine Kelly, who plays people like puppets. She holds the key to the hero’s success, and she holds it tightly.