Anthony Foyle, Lord Gillingham

Anthony Foyle arrives at Downton as an old family friend, easy company and clearly taken with Lady Mary. Heir to his own estate, he's polite, good-humoured, and unhurried in his courtship, content to let old affection resurface naturally rather than press his case.

Tom Cullen plays him without the usual aristocratic swagger — Gillingham is gentle and a little wistful, which makes him a genuine romantic option rather than an obstacle for Mary to overcome. The character works because he seems, at first, almost too straightforwardly kind for this world.