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 Whitacre decided to blow the whistle on a global price-fixing scam in the agricultural industry by turning informant for the FBI.

By agreeing to wear a wire to various meetings, Whitacre 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, with Matt Damon as the brilliant biochemist.

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 30lb 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!”

• See The Informant! at the Empire