The July 25 finale of “Superstar,” Andrew Lloyd Webber’s U.K. primetime TV star-search for a rock singer to play Jesus in an arena tour of “Jesus Christ Superstar,” proved one thing: The composer-producer may be losing his Midas touch.

Back in 2006, Lloyd Webber invented the idea of casting legit tuner leads live on TV. He took the format to the BBC and, together with stage producer David Ian, came up with ratings hit “How Do You Solve a Problem Like Maria,” a Saturday night show on BBC1 that climaxed with the public voting to cast hitherto unknown Connie Fisher in the lead role of “The Sound of Music.” Fisher immediately went into rehearsals for Lloyd Webber’s production, which ratcheted up a spectacular box office advance, won strong reviews and did stellar business.

The TV show made Lloyd Webber, previously not noted for his smallscreen work, an instantly recognizable media presence not only for musical theater but also for TV producing.

Further casting-shows aped “Maria’s” success. Ian took the format to rival U.K. broadcaster ITV to cast a production of his property “Grease” (the TV show flopped), but Lloyd Webber stayed with the BBC for successive hit shows for “Joseph and the Amazing Technicolor Dreamcoat,” “Oliver!” and, in 2010, “Over the Rainbow,” casting Dorothy for his production of “The Wizard of Oz.” The last of these averaged 5.45 million viewers.

His 12-part series “Superstar” for ITV1, however, has been both a critical and ratings disaster.

It debuted July 7 with just 3.2 million viewers; compare that with ITV1’s most recent run of “Britain’s Got Talent,” which averaged 10.01 million. Worse still, the numbers kept dropping. Following four introductory episodes screened over nine days, the channel chose to broadcast the show five nights a week, with the contestants being eliminated one by one at 9 p.m. Monday through Friday. The first elimination show managed 2.9 million viewers, the second just 2.37 million. Overall, the series averaged 2.7 million — considerably lower than ITV1’s advertisers had hoped.

Critics and viewers using social media and online forums were quick to try to diagnose the show’s problems. Airing nightly meant that rehearsal time was restricted, thus putting pressure on the show’s host, Amanda Holden. She’s immensely popular as a “Britain’s Got Talent” judge, but had little or no experience as a presenter anchoring a live show as complex as “Superstar.”

And then there were the three judges sitting alongside Lloyd Webber. Ex-Spice Girl Mel C (Mary Magdalene in the forthcoming arena tour) earned solid marks, but ex-pop star Jason Donovan proved, at best, platitudinous, while the presence of writer and comedienne Dawn French, of TV comedy favorites “French and Saunders,” added laughs but no expertise, according to pundits and the public.

The ratings slide induced a degree of panic at ITV. The program itself and its voting format was changed throughout the first week to try to increase the show’s tension. As online message-boards showed, that caused confusion among viewers over exactly when they could and couldn’t vote for their favorite performers.

Maybe the series’ producers should have listened to “Jesus Christ Superstar” lyricist Tim Rice. When the idea of a competition show to find the musical’s star was first raised, Rice said that casting Jesus on TV was “tasteless.” Hearing the show’s innumerable references to “salvation night,” “tomorrow is judgement day” and, most often, descriptions of Lloyd Webber as “The good Lord” (a reference to the title conferred on him by the Queen in 1997), it’s hard not to agree with Rice.

The combination of critical and public disfavor suggests that although “Superstar” may yet yield audiences for the 13-date U.K. tour, the chances of Lloyd Webber ever being able to do another TV casting-show seem slim.

The failure of “Superstar” to catch on, plus the early demises of much-trumpeted “Phantom” sequel “Love Never Dies” in London and “Jesus Christ Superstar” on Broadway, as well as the upcoming shuttering of his “The Wizard of Oz” after 18 months of less-than-boffo biz, it’s hard not to conclude that brand Lloyd Webber is beginning to look tarnished.

But with “Phantom” still afloat and Ricky Martin keeping “Evita” in Broadway’s millionaire’s club, he can yet thank heavens for a few things.