Don Farrell

Known in his home state as the Godfather or the Pope, Don Farrell was one of the players in the coup that brought down Kevin Rudd in June 2010. He also orchestrated this month’s mugging of South Australian Premier Mike Rann, although he left the deed to others.

And although you may never have heard of him, this softly-spoken Labor powerbroker has actually been king of the hill in South Australia for the past two decades.

''Don has absolute power in the Right,'' says the ALP's former deputy leader Ralph Clarke. ''He controls the pre-selection directly or indirectly of every MP in South Australia. If you want to get on, you get on with Don.''

Farrell also decides who is the state's Labor leader – which means he has been busy in recent weeks – and who gets into Cabinet. At the end of the day, it is a simple proposition, explains Clarke: "He has got the numbers."

Farrell grew up in an Irish Catholic family, and his father Ted founded the Catholic DLP in South Australia. He spent his childhood handing out election leaflets for his dad, who tried six times to get into parliament, without success.

Since 2008, he has been a senator in Canberra, where he carries the flag for the right-wing Shoppies union, the Shop, Distributive and Allied Employees Association (SDA), and leads the charge against gay marriage and just about anything else of which conservative Catholics disapprove.

Farrell got his ticket to the capital by dumping sitting Labor senator, Linda Kirk, who made the mistake of backing Rudd for leader in December 2006 despite a call from Farrell telling her not to. She then voted in favour of stem-cell research and the RU486 abortion pill, which the Shoppies adamantly oppose.

''I have lived by the union and died by the union,'' Kirk admitted, conceding that Farrell had given her the senate seat in the first place: ''He hand picks everybody and I was a beneficiary, there's no doubt about that.''

Kirk had fallen out with Farrell's wife Nimfa just before she resigned, and insiders believe this may have settled her fate. ''Don's an easy-going guy,'' says one Labor insider, ''but you don't want to cross him. He has a nasty streak.''

Farrell has devoted his life to the Shoppies, joining the union as an organiser in 1976 at the age of 22, after finishing his law degree. By the late 1980s he was the SDA's South Australian boss and a major force in the Labor Party. It was Farrell who made Mike Rann leader in 1994, promising him two terms in power, and Farrell who was instrumental in unmaking him in August 2011.

To build his dominance, Farrell parlayed the union's big block vote at ALP state conferences to forge an alliance with the Left (widely known as The Machine) so he could crush his rivals in the centre.

Farrell also sent his SDA organisers around ALP branches to sign up new members, which gave him yet more power and yet more delegates to state conferences. ''He's very good at that,'' says one Labor insider. ''And he's been doing it for 20 years or more. The boys in short trousers who once organised Labor branches for him are now ministers in Rann's cabinet.''

At least half a dozen current or recent state cabinet ministers are from The Don's inner circle, including Treasurer Jack Snelling, former attorney-general Michael Atkinson, and Industry Minister Tom Koutsantonis, who has survived despite racking up $10,000 in traffic fines. So too is a former minister who is now facing child porn charges.

Four of these men are former officials of the Shoppies union. Three are devout Catholics. The other is both.

Farrell has also installed his mates into Federal Parliament, where Kate Ellis (who helped count anti-Rudd votes on the night of the coup), Amanda Rishworth, and Nick Champion are all ex-SDA staffers.

Even so, Farrell wields his power quietly, behind the scenes. ''He's not a social animal,'' says one Labor insider. ''He doesn't work the room.''

Nor does he have to give orders. ''Don's supporters know what he wants, or think they know, and know they'll be rewarded. He wouldn't have to tell them which way to vote.''

And despite his role as a moral crusader, he never preaches. ''I don't think I've ever heard him talk about his religion,'' the insider adds. ''Not like Joe de Bruyn (the Shoppies National Secretary), who wears it on his sleeve.''

''Don's got the union in his DNA. He wants a good deal for his workers but he's not passionate about much else. He likes being able to put people in positions and he enjoys having power. He wants it for its own sake, not for what he can do with it.''