WHAT do Jessie J and Billy Liar have in common? It’s that they’re both advocates of the theory that if you tell a big lie often enough, people will start to believe it.

And boy, Jessie J’s come out with some whoppers, these past five weeks, on The Voice: “We’re not here to judge, we’re here to critique.”

(Or “judge”, to put it another way.) “Nate James, I’m happy you came on the show. It shows how credible the show is.”

And the classic: “It’s all about the voice.”

That’s what BBC1 would have you believe about its £22 million karaoke failure.

But you don’t have to dig very deep to discover its hypocrisy.

Will.i.am to Cleopatra’s Cleo Higgins: “Come to my team and I’ll make sure you get the right lighting and the right stage presence when you’re performing.”

Yeah, because it’s all about “the voice”, apparently, a catchphrase that becomes more baseless with the procession of sob stories, which now include shyness, for crying out loud, and the focus on contestants’ charity work / animal rescuing / special needs teaching.

It’s the biggest frustration I have with television’s most sloppily, choppily edited show, which looks even worse compared with even a misfiring Britain’s Got Talent.

Aside from two extra blind auditions shows (ooh, lucky us), nothing has changed, let alone improved since series one.

Danny O’Donoghue cannot make up his own mind, steals will.i.am’s soundbites, and found himself telling 40-something duo Diva: “The only reason I didn’t turn round is that duets scare me.”

Says the man whose last big hit was a collaboration with will.i.am.

The Black Eyed Peas frontman in turn speaks only in code: “For me to hang out with the eagles, the duck that looks like a duck has to work extra hard.”

Erm... right.

Holly Willoughby is getting away with the worst links on TV: “Just up from Wales you’ll find Blackpool...” and announced a pair of wet drips by saying: “Here come Harry Smith and Katie Jones,” only for the couple to introduce themselves afterwards as: “Katie Smith and Harry Jones.”

And the show could really do without the pandemic of acoustic guitars, has-been stars from the Nineties and Noughties, tribute acts and musical theatre pigeonholes.

Above all else, though, it needs to ditch Jessie J, a woman who it might surprise you to learn is a woman: “I feel like as a female, they will never understand how nerve-racking it is to be a female on stage.”

“If anyone knows what it feels like to be a female in this environment, it’s me.”

She goes around mistaking viewers’ intelligence for amoeba, feeling the need to point out: “We are literally facing the other way,”

and, having filled ten of her 12- strong team, said: “There are only two spaces left and then there will be none.”

Though she probably did have to explain the show’s dummy-proof format for Jessie J superfan Lemuel Knights who shared his pre-audition tactics: “I’m going to try to avoid eye contact.”

Shouldn’t be that hard, Lemuel.

What with them facing the other pigging way.

Her biggest crime, however, is the precious little joy she sucks out of a series that takes itself way too seriously anyway and had no qualms in showing a duo explaining their stage name last Saturday night: “Nu’tana means progression on a large scale. It’s from a spiritual book.”

Jessie J just makes matters a whole lot worse: “This isn’t just a TV show. This isn’t just ‘Oh, I’m going to go to The Voice, this going to be fun’. This is really serious.”

She’s right. It’s no fun at all.

And if I say it often enough, perhaps the BBC will start believing it.

Spudulike awards

● David Walliams, the only judge who gets Britain’s Got Talent.

● The Job Lot’s Sarah Hadfield proving she can do comedy after all, despite appearing on Miranda.

● Sky1’s lovingly crafted Greggs: More Than Meats The Pie, especially the bakery chain’s big boss driving to work over the Tyne Bridge to The Sopranos’ theme Woke Up This Morning.

● UCL’s Adam Papaphilippopoulos almost sending University Challenge’s voiceover man into spontaneous combustion every time he announced his name.

● Aardman clay model Ed Miliband appearing over Daybreak’s news caption: “Record levels of animal cruelty reported by the RSPCA.”

Poor Gromit.

● And Julie ‘Hayley Cropper’ Hesmondhalgh’s husband Ian revealing on All Star Mr & Mrs: “When we first got together, Julie had a pink caravan called Lola.”

Shortly after having the op and joining Corrie, presumably.

Spuduhate awards

● David Tennant’s terrifying hair highlights on The Politician’s Husband.

● Lauren Laverne hanging around like a guff in a stationery cupboard, on 10 O’Clock Live.

● The Wright Way’s script sounding like it’s begging for assisted suicide: “We’ve got to stage an intervention.”

● TV’s least original and most pointless show of the year, Channel 5’s The Truth About Travellers, with such insights as: “Weddings in the traveller community have become quite elaborate.” You dare say.

● Sitcom Vicious, a thesp-off between Ian McKellen and Derek Jabobi, turning into biggest gathering of luvvies on ITV since The Olivier Awards, 24 hours earlier, and in need of a new name: Rising Camp.