We all want to do the right thing, but few of us ever put ourselves on the line for the sake of a greater good.

In the early 1990s, family man Mark Whiteacre decided to blow the whistle on a global price-fixing scam in the agricultural industry by turning informant for the FBI.

He was the highest-level executive in American history to turn against his employers.

By agreeing to wear a wire to various meetings, Whiteacre provided the authorities with that essential link to the boardrooms of Archer Daniels Midland (ADM), where all of the decisions were made behind closed doors.

FBI agents were delighted as the case slowly but surely took shape, but there was something that their star witness was keeping from them.

Great swathes of his testimony and his snippets of insider information were the product of a fertile and overly-active imagination.

He also neglected to mention around $9 million in embezzled funds, one of the perks of his position as a company vice-president.

Steven Soderbergh recounts this incredible true story of bluff and bluster in The Informant!, adapted by Scott Z Burns from Kurt Eichenwald’s book of the same name.

Whiteacre (Matt Damon) is a brilliant biochemist at agricultural conglomerate ADM.

He has a beautiful wife Ginger (Melanie Lynskey), who is dedicated to him and their children, and a rosy future.

A tip-off from a Japanese rival suggests there is a mole in the company who is sabotaging the plant, so Mark’s bosses call in the FBI.

A routine visit from FBI Special Agent Brian Shepard (Scott Bakula) to install a wire tap at the Whiteacre family home, leads to a shocking revelation: Mark’s bosses are party to a worldwide price-fixing scam.

Brian is stunned and, after consulting his bosses, he and partner Bob Herndon (Joel McHale) prepare Mark for a role as a snitch, unaware that the family man is leading them all up the garden path.

The Informant! is a fascinating and at times amusing true story about an everyman who pulled the wool over the eyes of some of the US Government’s most highly-trained officers.

Damon gained 30lbs and an unflattering moustache for the role, delivering a tour de force performance as a man lost in his own web of lies, deceit and insider dealing.

A voiceover reveals some of the truth of Mark’s feelings as he imagines himself a hero in one of his favourite John Grisham page-turners.

“Didn’t these people see The Firm? Everything these people did to me, they did to Tom Cruise!”

When the truth about Mark’s actions is revealed, we begin to squirm in our seats as he attempts to dig himself out of a hole with even more fibs, but only ends up going deeper and deeper, past the point of no return.

STAR RATING: ***