The appointment of Paul Barry to replace Jonathan Holmes as presenter of the ABC1 Media Watch program has drawn attention, once again, to the absence of conservatives as presenters on the taxpayer-funded public broadcaster.

Barry is but one in a succession of leftists or left-of-centre presenters since Media Watch started in 1989. Namely, Stuart Littlemore, Richard Ackland, Barry (the first time round), David Marr, Liz Jackson, Monica Attard and Holmes.

The fact that the ABC has become a conservative-free zone is not an accident of history.

In late 2004, when he was presenting Media Watch, Marr explained and rationalised the phenomenon in a speech at the University of Technology, Sydney. He described journalism as a ”soft leftie kind of culture” and declared that if journalists ”don’t come out of this world” they should ”find another job”.

In recent days, ABC managing director Mark Scott has seen fit to defend the ABC against the criticism that it does not have one conservative presenter of any of its main current affairs programs.

He was asked about this matter during interviews on Thursday with Rafael Epstein on 774 ABC Melbourne and Jonathan Green on RN Drive.

Both times, Scott went into spin mode. He recalled an occasion when former presenter of The 7.30 Report Kerry O’Brien had done an interview with John Howard and there had been complaints O’Brien was too tough and too easy on the (then) prime minister. This did not answer Epstein’s point that ”there’s a lot of people who think there’s too much of the left and not enough of the right on the ABC”.

Scott overlooked the point that if a former Labor employee such as O’Brien can do the job then, presumably, a former Coalition employee can do likewise. It’s just that the ABC has none of the latter in key positions in front or behind the microphone or as editor of online magazine The Drum.

In his interview with Green, Scott dismissed the criticism that the ABC has no conservative presenters on any of its main programs as ”simplistic” and ”absolutely simplistic”. But this could only be the case if you accept that, say, the likes of Fran Kelly and Phillip Adams dump their views at the studio door when they present Radio National Breakfast and Late Night Live.

Bill Peach and Littlemore worked on This Day Tonight (The 7.30 Report’s predecessor) in the late 1960s and early 1970s. In their subsequently published memoirs, both admitted they used their positions to rail against political conservatives.

In his interview with Epstein, Scott defended the evident lack of balance within Radio National by stating ”we have Amanda Vanstone”. Vanstone is a small ”l” liberal whose program is labelled Counterpoint (get it?) and airs at 4pm on Monday. Her appointment does not address the absence of conservatives on key programs.

Scott also denied that the former ABC chairman Maurice Newman has criticised a culture of ”groupthink” at the public broadcaster. But Newman has made this criticism – when he was at the ABC and subsequently.

Newman is upset about the groupthink at the public broadcaster on climate change. There is a similar groupthink on such issues as same-sex marriage, the coalition of the willing’s invasion of Iraq and more besides.

In talking to Green, Scott said there was adequate diversity on ABC TV and pointed to such programs as InsidersQ&A and The DrumInsiders and Difference of Opinion (predecessor to Q&A) were established before Scott became ABC managing director. Moreover, The Drum, which airs on News 24, often runs panels where everyone agrees with everyone else – most recently last Friday, when the presenter and the three guests all lined up in support of same-sex marriage. There was no debate and, consequently, the segment was boring.

When Scott became ABC managing director in 2006, he promised that a ”further diversity of voices” would be heard on the public broadcaster under his watch. This has not occurred.

And now the ABC managing director is asserting it is ”absolutely simplistic” to refer to the dearth of conservatives in his organisation.

The ABC recently received an extra $10 million handout from the government, which will be used to establish a fact-checking unit. If the money were used to check its own material, well and good. But the ABC is now proposing to check the facts of political parties and other organisations. In view of the reality that the ABC remains a conservative-free zone, this is likely to cause some controversy. Probably more than Barry’s second coming as Media Watch presenter.

Gerard Henderson is executive director of the Sydney Institute.