To enjoy productions on BBC America, a viewer must have a stiff upper lip and an Anglophile ear.

Yes, the dialogue, particularly on dramatic programming, is often difficult to grasp, even for viewers with perfect hearing. Fortunately, this is only a minor problem in The State Within, a six-hour miniseries premiering tonight. It's a roller-coaster espionage thriller.

The setting is modern Washington, D.C., where the British heroes and bad guys regularly mix with their U.S. counterparts in a high-octane drama. Is it my imagination or do British accents automatically tone down when actors are in scenes with U.S. performers?

The drama begins when a commercial flight headed for London explodes during take-off from Washington's Dulles Airport. Is America again under attack?

As a shocked Washington struggles to come to terms with the disaster, a diplomatic catastrophe envelops the British embassy, as evidence seems to suggest that a British Muslim was behind the attack.

But such an accusation is only the tip of an espionage iceberg that involves a host of good and bad guys from both countries. Paranoia and ambiguity run rampant along with political scheming, continued violence and a bit of sex and romance.

Several subplots, including ones dealing with a black man on death row in a Florida prison and a potential war against a central Asian country, seem to have nothing to do with the all-important bombing puzzle.

But scriptwriters Lizzie Mickery and Daniel Percival tie up everything during a fast-paced, logical ending.

Acting, particularly by the two central figures, is superb. Jason Isaacs (Showtime's Brotherhood) is beleaguered British ambassador Sir Mark Brydon; Sharon Gless plays Lynne Warner, the steely-eyed, nasty-talking U.S. Secretary of Defense who has no love for the Brits for personal and political reasons .

Yes, that Sharon Gless of Cagney & Lacey fame, minus the glamour and rollicking sense of humor.

Top-notch production values and swift camera work, always trademarks of British action and dramatic series, are on display throughout.

The opening scenes are a grabber as Sir Mark, witnessing the plane explosion from his car, attempts to rescue a woman trapped in the fiery debris on a freeway where the airliner has crashed.

My recommendation of The State Within comes equipped with this personal advisory: Pay strict attention to the often-convoluted plot. Don't watch while thumbing through a magazine or analyzing those holiday credit-card bills.

The series needs your rapt attention, even without any British accents.

The State Within

• What: Espionage rules in a six-hour miniseries.

• When and where: 7-9 p.m. today and Sunday, 7-9 p.m. Feb. 24, BBC America (found on digital cable and satellite services)

• The verdict: A fun thrill ride

saunders@RockyMountainNews.com or 303-954-5137