Two things become immediately clear watching PBS’ Brit-com import “Vicious”: One, the major networks wouldn’t touch it. And two, it’s too bad the show isn’t sharp enough to make them regret that bias. The taboo here isn’t that the main characters played by Ian McKellen and Derek Jacobi are gay, it’s that they fall far outside the 18-49 demo. While the material is about as classy as an average Chuck Lorre show, the name and very game cast — especially McKellen — should be a potent draw for PBS’ dedicated Anglophile aud.

Co-created by American TV vet Gary Janetti (“Family Guy,” “Will & Grace”) and British playwright Mark Ravenhill, the shamelessly broad comedy centers around the busy living room of egomaniacal small-time actor Freddie (McKellen) and his partner of nearly 50 years, Stuart (Jacobi, also featured in PBS’ “Last Tango in Halifax”).

They’re frequently visited by randy best pal Violet (Frances de la Tour) and the happy-go-lucky young hunk from upstairs, Ash (Iwan Rheon, 180 degrees from playing vile villain Ramsay Snow on “Game of Thrones”), the perpetual target of misguided flirting from Freddie and Violet alike.

While the quality of the cast may inspire hopes of a sophisticated laffer, “Vicious” is a pointed throwback to ’70s era schtick with decidedly un-P.C. humor and farcical plotlines that wouldn’t feel out of place in a “Three’s Company” rerun. The bulk of the first episode involves determining whether Ash is straight or gay, and later installments include Freddie’s concern Stuart might be unfaithful and Ash landing a gig as a club promoter, inviting his senior friends out for the night (he’s “paid by the head,” though Freddie hears that differently).

It’s all filmed in front of a live audience, on a noticeably theatrical stage complete with a grand staircase for McKellen and Jacobi to alternate dramatic entrances and exits as needed.

McKellen turns out to be the show’s not-so-secret weapon. A great actor playing a mediocre one, he’s somehow entirely convincing in the part (the thrill Freddie feels over an audition to play “Cook Staff #4” on “Downton Abbey” is palpable) and particularly adept at delivering Janetti’s acid-tongued putdowns and sarcastic asides.

That’s where the “Vicious” title comes from. Freddie and Stuart prove unrelenting in their bitchy barbs about age, appearance, intellect and background, directed both at each other and their friends. The mean-spirited (if ultimately loving) nature of the series could easily be a turn-off for some. Others will simply wish the writing was as consistently clever as McKellen’s line readings.

Still, “Vicious” doesn’t need to be perfect to score. With U.S. networks stubbornly uninterested in exploring the lives of people over 60, PBS could find an untapped audience for the six-episode first season. And cancellation won’t be a concern: the show was successful enough on ITV in the U.K. to merit a second season, expected to premiere across the pond later this year.

TV Review: ‘Vicious’

(Series; PBS, Sun. June 29, 10:30 p.m.)

  • Production: Filmed in London by Brown Eyed Boy in association with Kudos and Nickelby Inc.
  • Crew: Executive producer, Gary Janetti; consulting producers, Mark Ravenhill, Jemma Rodgers; producer, Gary Reich; director, Ed Bye; writer, Janetti; camera, Tony Keene; production designer, Harry Banks; editor, Chris Wadsworth; casting, Toby Whale, Marilyn Johnson. 30 MIN.
  • Cast: Ian McKellen, Derek Jacobi, Frances de la Tour, Iwan Rheon, Marcia Warren, Philip Voss.