Allen Leech finds a happy home at ‘Downton Abbey’

This photo provided by PBS/Masterpiece shows, from left, Allen Leech as Tom Branson, Tom Cullen as Lord Gillingham, and Michelle Dockery as Lady Mary, in a scene from season 5 of “Downton Abbey.” The show premieres Sunday, Jan. 4, 2015 on Masterpiece on PBS. AP

BEVERLY HILLS, Calif. – “Downton Abbey” star Allen Leech has a winning way with accents.

The Irish-born actor employs his native brogue in portraying Tom Branson, the former chauffeur who’s become a landed-family insider on the PBS series that returns Sunday for its fifth season. But moviegoers hear a Scotch lilt from Leech’s World War II code breaker in “The Imitation Game.”

And, for an audience of one, Leech seals his adroitness with an impish take on the posh English tones of “Downton Abbey” creator and writer Julian Fellowes.

When a nanny was discovered mistreating Tom’s toddler daughter last season, Leech recalls, he asked Fellowes if Tom could punish the wayward servant.

“I don’t think another death on our hands is what we need,” Leech said, mimicking Fellowes — who, despite asking, has yet to hear the canny impression.

“As soon as he fires me,” Leech said, smiling.

There appears little danger of that. Leech’s Tom has become an integral part of Lord Grantham’s estate and the series. Tom may lack the elan of the late, lamented Matthew, but his solid warmth, coupled with Leech’s helpful handsomeness, make him a worthy Downton leading man.

During a promotional visit here for “Downton Abbey,” Leech was careful to avoid giving away details of the latest season — which, to the frustration of some viewers, comes to America after it airs in the U.K. — but he was willing to revisit past threads that are woven in for his character.

Tom, a single father since the death several years before of his high-born wife, is increasingly uneasy in the embrace, however kind, of his wealthy in-laws. Fanning his discontent: an attractive woman who wants him to return to his onetime radicalism.

Teacher-firebrand Sarah Bunting, played by Daisy Lewis, “certainly has reignited his passion for political life but also for change,” Leech said. That has Tom seriously mulling a different life in America for him and his daughter.

“Bear in mind, the family aren’t enamored of him going anywhere, which is a long way from season two,” he said, laughing over Tom’s rocky path in wooing Lady Sybil.

Leech’s career has moved along nicely since he found, as a child appear