PBS’ Beloved Det. Tennison Has Become Half ‘Suspect’

It’s just a bit sad when a legend fades.

So it is with “Prime Suspect,” Granada Television’s series of fictional stories about the turbulent career of Jane Tennison, a whiz of a senior British police detective (played marvelously by Helen Mirren) whose rise in the London ranks has been slowed by jealous male rivals and her own personality, which at times is irritating and self-destructive.

As is “Prime Suspect” itself, unfortunately.

At its best, it’s been extraordinary, standing in a tiny stratosphere of elite television drama worthy of bronzing. Thank the Brits, for nothing on U.S. television has outperformed this import.

Then there’s the melted-down “Prime Suspect,” which describes two previous efforts and a chunk of the latest, “Prime Suspect 5,” an ultimately disappointing two-parter (totaling four hours) arriving on “Masterpiece Theatre” Sunday.

Always a pain in the rear to somebody, the now-50ish Detective Supt. Tennison has been exiled to Manchester, where she finds herself heading a murder probe involving the drug culture and getting the usual reluctant support from some of her subordinates.

Some of Guy Andrews’ teleplay has an arresting edge, and director Phil Davis keeps things interesting throughout Part 1 and the first half of Part 2, with Tennison blundering into another unwise affair and making other missteps (the kind that humanize her and increase her appeal) while trying to keep pace with a local crime lord who delights in taunting her.

As always, there’s her own boss to contend with, and this time also a traitor, whose identity seems rather obvious, and certainly should be to someone as perceptive and susceptible to paranoia as Tennison. Yet inexplicably, she’s in a fog.

Much worse, the concluding hour is a catastrophe that transforms Tennison (whose attributes have always been cerebral) into an action cop who single-handedly and suicidally charges after a crazed killer in a madcap finale that resonates formulaic plotting. The old Tennison would have walked out.

Steven MacKintosh works well as the story’s psychopath, and Julia Lane and David O’Hara are persuasive as Tennison’s underlings. And there is Mirren--the one constant throughout “Prime Suspect,” since its inception in 1992--whose intelligence has never faltered, even when in recent years the writing behind her has.

Although you hate to see a female protagonist as formidable as Tennison check out, it may now be time for her to leave, before “Prime Suspect 6” turns her into Batgirl.

* “Prime Suspect 5” airs on “Masterpiece Theatre” Sunday at 9 p.m. on KCET-TV Channel 28.