The release of celebrated investigative reporter Chris Masters' latest book, a history of Australian special forces in Afghanistan, has sparked intense debate within Defence circles over the past week.

That debate has spilled over on to the pages of newspapers, as a result of Masters' decision to include some material about Australia's most decorated soldier, Victoria Cross winner Ben Roberts-Smith.

In the book, No Front Line, Masters draws attention to discrepancies between accounts of an incident in Afghanistan in 2006, in which Corporal Roberts-Smith and a fellow SAS member, the late Matthew Locke, hunted down and killed an Afghan who they suspected of being a spotter for Taliban.

Different accounts

According to accounts given to Masters, the Afghan was an unarmed teenager, and other SAS members had already decided it was not necessary to kill him. In later interviews given to the Australian War Memorial and The Australian newspaper, however, Corporal Roberts-Smith variously said there were two Afghan men, and an armed Taliban insurgent.

In the book, Masters says that when he drew these discrepancies to Corporal Roberts-Smith's attention, the former SAS sniper wrote to the War Memorial to correct the record, saying the six-year gap between the events and the interview, plus the sheer number of tours of Afghanistan he had been on, had clouded his memory.

Victoria Cross recipient Ben Roberts-Smith on Anzac Day last year. ( ABC News: Ian Cutmore )

In an interview with The Australian at the weekend, Corporal Roberts-Smith lashed out at Masters, saying he did not understand why he would devote part of his book to this event, and that he was sullying the memory of Sergeant Locke, who was killed in action a year later.

Corporal Roberts-Smith went further, saying scrutiny of SAS actions in Afghanistan was "un-Australian". In this, he was echoed by Brendan Nelson, formerly a defence minister and now director of the Australian War Memorial, who, despite not having read Masters' book, said "sanctimonious … armchair lawyers" should not be second-guessing the actions of special forces in Afghanistan.

Persistent dark rumours

Let's be clear, the vast majority of Masters' book is an uncontroversial, straight-up-and-down recounting of the operations carried out by our SAS and commandos in Afghanistan. Masters' well-documented regard for our special forces is evident, and there is enough "bang-bang" and detailed descriptions of various battles to keep any military geek happy.

But a journalist of Masters' repute could never ignore the persistent dark rumours that have circulated for years. Rumours about unofficial "kill competitions", about the reluctance to take Taliban prisoners, about the planting of weapons on dead Afghans, about steroid abuse and bastardisation.

These rumours are the subject of investigation by Paul Brereton, a NSW Supreme Court judge and Army Reserve Major General, who is running a secretive inquiry on behalf of the Inspector-General of the Australian Defence Force.

The ABC revealed earlier this year Justice Brereton had gone beyond the investigation of rumour and innuendo, and was examining concrete allegations of wrongdoing, including a number of incidents in which children and unarmed Afghans were killed, and weapons allegedly planted on dead bodies.

Justice Brereton's inquiry has all the powers of a royal commission, including the ability to compel people to answer questions, and recently issued a highly unusual public call for information. Defence insiders say the inquiry is struggling to break the special forces code of silence.

'A personal tragedy', not the nation's

It is difficult to understand the reasoning of those who say we should forget about Afghanistan, and apply no scrutiny to what our special forces soldiers might or might not have done there.

There are those who place these men on a pedestal, telling the rest of us they are beyond reproach and should be the recipients of nothing but gratitude. It's worth noting, as Masters does, this is not a view shared by all soldiers themselves.

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"We as a nation have lost 40 soldiers in almost a decade of war. I know American guys who lost that many from a single tour," Masters quotes an anonymous SAS member as saying.

"We mourn the loss of a soldier as a national tragedy, when in fact it is not.

"It is a personal tragedy for the unit, his family and his mates, but nothing more than that.

"Prime ministers and opposition leaders attend ceremonies that should be reserved for friends, family and brothers-in-arms. What makes a soldier's death anymore significant than that of a volunteer firefighter, killed defending the property of someone he has never met?"

Masters also quotes a Lieutenant Colonel who commanded regular Army troops in Afghanistan as saying: "The hyperbole surrounding the contribution of Australian soldiers in Afghanistan makes the soldiers feel entitled to be treated as Roman gladiators."

It is unfortunate it still apparently needs to be pointed out, but we should be worried when legitimate questions about what is done in our name, to an impoverished people on the other side of the world, are deflected with accusations of disloyalty.