THE INVENTION OF LYING (12A).

Comedy/Romance. Starring Ricky Gervais, Jennifer Garner, Rob Lowe, Louis CK, Jeffrey Tambor. Directors: Ricky Gervais, Matthew Robinson.

The truth about Ricky Gervais’s new comedy, co-written and co-directed by Matthew Robinson, is that it is mean-spirited, misconceived and starved of big laughs.

Set in an alternate reality in which everyone instinctively tells the truth and the concept of a fib doesn’t yet exist, The Invention Of Lying is ripe with comic potential.

Sadly, Gervais and Robinson take their central dramatic conceit to garish extremes, having characters converse with brutal honesty, regardless of the hurt they might cause.

It’s not enough for a woman to politely rebuff a man’s offer of a date with a simple ‘no’: she has to crush what remains of his shattered self-confidence with a barrage of insults.

When another character discusses his feelings, he confides: “Sometimes I cry in my sleep and wake up in a pool of urine.”

This sadistic streak runs throughout the screenplay, sporadically vanishing for a handful of touching and poignant scenes like a son tearfully bidding farewell to his dying mother.

Predictably, Gervais casts himself in the lead role and, as with Ghost Town, he’s an unsympathetic and unconvincing romantic lead.

The notion that Jennifer Garner’s acid-tongued beauty might succumb to his so-called charms is more laughable than anything in the script.

Lowly screenwriter Mark Bellison (Gervais) is about to be fired by his boss Anthony (Tambor) and his landlord is demanding rent money he doesn’t have.

So he heads for his bank to close the account.

Asked by the teller how much he wants to withdraw, Mark suffers a moment of blinding realisation and... tells a porky, asking for $800 rather than the $300 he actually has to his name.

Having stumbled upon the art of lying, he begins to exploit deceit for personal gain at the roulette table with best friend Greg (Louis CK).

He also wins the affections of the lovely Anna McDoogles (Garner) and impresses Anthony with a wacky screenplay about a spaceship landing during the time of Black Plague, which everyone accepts as historical fact.

As Mark grows increasingly comfortable with lying, he realises there are grave consequences to leading people astray.

The Invention Of Lying is an unnecessarily crude subversion of polite social mores, littered with cameos from the likes of Stephen Merchant, Christopher Guest and Edward Norton.

Gervais’s trademark bluster grates and we lose patience completely when he stands before the world to deliver a 21st Century 10 Commandments, sellotaped to the back of pizza delivery boxes in place of stone tablets.

Tina Fey, easily the most gifted comedian in the entire film, is squandered in a thankless role as Mark’s embittered secretary.

There are occasional chuckles, like a retirement home being called A Sad Place For Hopeless Old People, but they are lamentably few and far between.