A new documentary about convicted Australian war criminal and bush poet Harry "Breaker" Morant will prove he was not a pathological liar and his trial a farce.

That's the opinion of Australian actor and writer Neil Pigot, who spent months unearthing new evidence about the bush legend who, with Lieutenant Peter Handcock, was executed in 1902.

The pair were tried and convicted for killing prisoners and a German missionary during the Boer War.

Their trial and subsequent execution by the British has long been the subject of movies and books.


There have also even been recent attempts to have the pair posthumously pardoned.

Breaker Morant: The Retrial, which Pigot narrates, airs tonight on Sky's History Channel and is the latest instalment about Morant's controversial court-martial.

Pigot says they have uncovered new evidence which proves Morant was not a liar, which was one reason why his claim, that he followed orders and shot prisoners, was heavily discounted.

However, Pigot visited the descendants of a British admiral and says the revelations are startling.

"Historians, generally speaking, have always considered him to be a pathological liar because he continuously claimed to be the bastard son of Admiral [George] Digby Morant," Pigot said.

"So they've taken that aspect of his character and applied it to his claim that he was given orders to take no prisoners.

"We have found there is an overwhelming body of circumstantial evidence that says he was the bastard son of Digby Morant ... he was basically telling the truth."

The documentary makers also interviewed the descendants of those executed by Morant.

Several prominent Australian legal eagles have also joined the chorus of discontent about Morant's trial, including Geoffrey Robertson, QC and Gerry Nash, QC.

"We're not taking a contemporary sensibility and putting it on to it," Pigot explained.

"Given the judicial and military system at the time, you ask did they follow due process, and it's absolutely clear they did not.

"More evidence has come to light since making this documentary, and another appeal is going ahead to the High Court in London."

The work explores the four-year campaign of military lawyer Jim Unkles and the descendants of Morant and Handcock to have the soldiers pardoned.

The two-hour episode also looks at the life of Morant, a well-known local poet who called Banjo Paterson and Henry Lawson mates.

Pigot said he's been intrigued with Morant ever since he saw the 1980 Bruce Beresford-directed movie Breaker Morant.

"He was an Australian bush legend and one of the most celebrated poets of his day," Pigot said.