Ian Townsend: Hello, I'm Ian Townsend and welcome to Background Briefing.

It was called an act of bioterrorism; the introduction of foxes into Tasmania more than a decade ago. Here's how it was reported on ABC Television's Catalyst program in 2002.

Journalist: Two years ago, a group of environmental vandals committed an unthinkable crime. They hand-reared up to 19 fox cubs and released them into the previously fox-free Tasmanian wilderness. It's hard to comprehend that such a petty act has unleashed the greatest extinction threat since Tasmania's last ice age 10,000 years ago.

Nick Mooney: Bringing foxes to Tasmania is probably the most foolish and stupid thing I could think of being done.

Clive Marks: I would call it an example of bio-terrorism. We're dealing with something which is akin to September 11 for our wildlife in Australia.

Ian Townsend: In response, the Tasmanian government started a decade-long multi-million dollar search and destroy program that's still going today, but has never found a live fox. It's been the subject of furious public debate and media speculation in Tasmania.

Now, an independent scientific review is saying the Tasmanian fox story is a myth. Leading that review is Dr Clive Marks. He helped set up the state's Fox Eradication Program. He now believes Tasmanians have been misled.

Clive Marks: Here is an example where you can propose that something exists when it doesn't, and if you follow that narrative with a suitable amount of media and spin doctoring you can get a good proportion of people believing it.

Ian Townsend: The story was that hunters released foxes across the Tasmania around the year 2000.

The director of the Tasmanian Conservation Trust, Peter McGlone, is on a government fox advisory committee, and he firmly believes that release did happen.

Peter McGlone: The investigation into the deliberate introduction of foxes that did take place, and I'm confident took place, was bungled.

Ian Townsend: How was it bungled?

Peter McGlone: It was bungled by the minister refusing to accept advice that to successfully prosecute those people who were known by authorities to have done this, they would have had to have retrospectively changed legislation, but it was the advice of the experts at the time that we have these people absolutely dead in the water, they are guilty as sin.

Ian Townsend: But police reports from 2001, obtained under Freedom of Information, show there was no evidence to charge anyone, retrospectively or not. The police dismissed the allegations as “hearsay”, “gossip”, and “rumour”. Despite that, Tasmanians have been told for years that the foxes really were released.

The police minister at the time was David Llewellyn, who was also the minister in charge of Parks and Wildlife. David Llewellyn's now an Opposition MP.

David Llewellyn: Senior people within the department of Parks and Wildlife gave me that advice and they were absolutely certain of the fact. Although it was somewhat dated by the time it had got to me, I initiated a police investigation which I'm not sure how thoroughly it was done, but there wasn't enough evidence to follow up from a legal point of view.

Ian Townsend: Did you see the police report when it was done, the report that said that the information that came from Parks and Wildlife was rumour and probably guesswork and some of it was highly suspect?

David Llewellyn: Well, I can't recall the details of that right now, but it was somewhat after the event.

Ian Townsend: But the original police report really dismissed all that evidence. Are you confident that Parks and Wildlife had enough information to go on to establish that foxes were in the state?

David Llewellyn: Well, absolutely. I mean, at the time it was quite a serious issue and I took the advice that I was given quite seriously.

Ian Townsend: For the first time, one of the hunters accused of importing those foxes is speaking publicly.

Adrian Donaldson: No one's brought any…I have not brought any foxes into the state.

Ian Townsend: Adrian Donaldson lives in the state's north, and his name appeared on a Confidential Briefing Note that was handed to the police minister back in 2001.

Adrian Donaldson: It's kind of a shock to even have you here speaking to me about the whole thing when it's just all made up.

Ian Townsend: We'll hear more from Adrian Donaldson later. A police task force interviewed the three hunters back in 2001. The commander of that police taskforce at the time was Ivan Dean.

Ivan Dean: Yes, they were spoken to and nothing came from that at all. Their evidence was plausible in all of the circumstances, and I then reported back to the Commissioner saying that there was just no truth in it whatsoever. From our point of view we could find no evidence at all and it was a thorough investigation, well done, some of the top detectives in the State at the time, they were on this investigation, so it wasn't something we treated lightly. We treated it as an extremely serious matter.

Ian Townsend: Ivan Dean is now a politician in the Tasmanian Upper House and he's a strong critic of the decade-long Fox Eradication Program.

Ivan Dean: There's been in the realms of about $50 million spent on this program, and when you look at the whole of the evidence on which this was built, it falls away to absolutely nothing, and in in my opinion it's been $50 million wasted.

Ian Townsend: The Fox Eradication Program in its various forms is administered by Tasmania's Department of Primary Industries, Parks, Water and the Environment, and the department has declined to comment. A former spokesman for the program, though, is biologist Nick Mooney, who left the department several years ago and is now a wildlife consultant.

Nick Mooney: We were confident the evidence showed that there was a high enough risk that something substantial had to be done. The simple fact is, if you wait long enough for everyone to be happy there are foxes in Tasmania or satisfied there are foxes in Tasmania it's too late to do anything, because there would have to be so many there that people start shooting them and, you know, we start shooting them or the police shoot one or whatever and it'll be too late to do anything. That's the problem.

Ian Townsend: Another problem, though, is that the eradication program's been running for more than a decade and it has not shot, photographed, or trapped a live fox, or found evidence of a baited fox.

A team of seven scientists has been reviewing the program and it's just published its report online. There's a link on the Background Briefing website.

Veterinary pathologist Dr David Obendorf is one of the authors

David Obendorf: The difficulty this program had was it used a great deal of propaganda and public relations to get across its message, but it failed to actually pass the first test which was the onus of proof test. People need to know that this has been independently, repeatedly demonstrated that you have got evidence that shows that the fox is in the landscape. So what we've got is a situation where the threat has always been a real threat for Tasmania, but the presence of evidence is completely zero

Ian Townsend: After more than 10 years, Tasmanians have become deeply sceptical about the foxes they've been told are in their midst.

I'm driving north from Hobart to what's considered fox central, the town of Longford, where three hunters were said to have brought in, raised and then released fox cubs.

Longford is off the main road, down a country lane lined with hedges. The countryside looks European. There are sheep and chickens in the paddocks. A fox wouldn't look out of place here.

In the centre of Longford village is the Blenheim Inn hotel.

Man: Foxes? Ha ha, what do want to know about them? I've got a shit-load them at home! You still got that fox out at your place?

Man: Fox? Yeah, why?

Ian Townsend: It's a Friday evening and people are coming in after work.

Man: Well, I hear a lot of people talking, they do a lot of shootin', there's no foxes about.

Ian Townsend: Nobody you know ever seen a fox?

Man: No.

Ian Townsend: Any of you guys?

Man: No mate, I don't reckon there is. I been shooting a fair bit myself and I've never seen one. If there is a fox about he's hanging out that Tasmanian Tiger!

Ian Townsend: Is a bit of a joke around here, the fox has become a joke?

Man: Yes, I'm sure it is. You know if there's scats around or whatever…like, anyone could have brought in from the other side or something or other, surely to God they should have them by now.

Ian Townsend: It was to Longford that the police task force came in 2001 to investigate a report that hunters had raised up to 19 foxes on a farm out of town, and then released them around the island to improve the hunting.

According to the police reports, it all started with a conversation at the back of a vehicle outside the Allgoods Store in the Hobart suburb of Glenorchy. An unnamed man was heard to say that hunters had brought fox cubs in from Victoria. The person who reported it said he thought at the time it was a joke, but on reflection told Parks and Wildlife officers.

By the time the story reached the Minister for Police, David Llewellyn, it had been put into a briefing note that contained names, places and times. The briefing note was passed to police, and five detectives were put onto the case. When they reported back in July 2001, they were scathing about what was in that briefing note. Here's a reading from the police report.

Reading: On investigation it became abundantly clear that the original informant (spoken to by police) had only passed on part of that information, most of which was hearsay and gossip. The remaining information seems to have come from Parks and Wildlife Service personnel who have relied on rumour and probably guesswork. None of the information was confirmed and some was found to be highly suspect.

Ian Townsend: You'd think it might have ended there, but that was just the beginning.

The police commander at the time, Ivan Dean, said that police report was handed to the Police Minister.

Ivan Dean: The Minister of Police at the time accepted that report. However, the Minister later went back on some of that information, after I guess following briefings from other sides.

Ian Townsend: The Police Minister was David Llewellyn, who was also the minister in charge of Parks and Wildlife. He's now an Opposition MP.

David Llewellyn says senior people within Parks and Wildlife persuaded him, in spite of the police report, that the event did happened. He says he's still convinced of it.

David Llewellyn: Well yes, I am, I think it was very seriously taken at the time and the people involved were quite, as I say, senior people within the department, and for not following the matter up I think that would have been a tragedy if we had seen the incursion develop into larger numbers of foxes in the state.

Ian Townsend: That campaign kicked off though on the basis of those foxes being released and it's since transpired that there was no evidence for that, the police report's quite clear…

David Llewellyn: Well, you're saying that, I don't believe that. I think there's a lot of evidence and I think that's authenticated by the scat evidence that's been seen since and certainly the very high number of people that have reported sightings of foxes in the state.

Ian Townsend: When the fox eradication campaign kicked off 12 years ago, one of the first people brought in was Dr Clive Marks, who we heard at the start of the program describing the introduction of foxes as the 'September 11' for Tasmanian wildlife. Clive Marks is one of Australia's foremost fox experts and at the time worked for the Victorian Government.

Clive Marks: It was initially indicated to me that the police had confirmed the release of these animals and that was without a doubt, but because it was sub judice, the details could not be provided. Now, given that was the story I received from at least two Tasmanian government employees at the time, I had no reason to doubt it.

Ian Townsend: One of those Tasmanian government employees was wildlife officer Nick Mooney. Here's Nick Mooney talking to Robyn Williams on the ABC's Science Show back in 2002.

Nick Mooney: Our information is that they were basically smuggled in by a vehicle on a ship.

Robyn Williams: And so presumably they were brought to shore and let free somewhere in the north of Tasmania?

Nick Mooney: Yes. Because this is all done in secrecy and it's very illegal, it's very hard to get a handle on what actually happened, and so of course our information is hearsay and we can only have a certain amount of faith in it.

Ian Townsend: But today, that faith has trickled away. Nick Mooney's on the phone from his home at Richmond in Tasmania.

Do you believe that actually happened, that cubs were brought in?

Nick Mooney: I don't know. To me it's a story, it might be a very credible story when told by some people, but I don't have a strong view of it, because I've seen no evidence.

Ian Townsend: But back in 2002, the respected journal Nature ran a story quoting Nick Mooney as saying: 'The information that authorities have received leaves no doubt that foxes were deliberately brought into Tasmania.'

It was such a serious claim that fox expert Clive Marks flew to Tasmania to help organise a national response.

Clive Marks: I had no reason to doubt that. So, of course, I worked on the basis anyway of the precautionary principle, which is something that is sensible to do to begin with, and we started to organise the response. So, yes, I had no reason at all to doubt the veracity of the claims.

Ian Townsend: Clive Marks says the precautionary principle was only triggered back then because authorities had assured him the foxes had been introduced. He went to Canberra to help organise funding, and then returned to his main job with the Victorian Government.

It wasn't until seven years later, when he was sent a copy of that original police report scotching the fox release story, that Clive Marks decided to take a closer look at all the other claims being made about foxes in Tasmania.

Clive Marks: And I was staggered by what I found. Thinking about this in sort of wider political terms is quite frightening, because you come up with a completely different interpretation about what's going on.

Ian Townsend: North of Longford on the road to Devonport is the quiet village of Westbury. It's here that I've found Adrian Donaldson, one of the three hunters named as suspects in the alleged fox importation caper, and questioned by police.

This is the first time that Adrian Donaldson has spoken publicly, and he says he's shocked anyone still believes that story.

Adrian Donaldson: I mean, I just believe it's bloody…it's all a myth, it is really a myth, I don't believe there's any foxes in the state.

Ian Townsend: The accusation originally was that you and a couple of other blokes had brought in fox cubs. Did the police ever talk to you about that?

Adrian Donaldson: I didn't even understand it back then, it was like 'you've got to be joking, that's absolute bulldust'.

Ian Townsend: That initial accusation that people brought in fox cubs still has some credibility.

Adrian Donaldson: To whom, to whom? Because for me I don't spend any time looking for foxes. I am a hunter, but there's no foxes in the state, there's a lot of hunters in the state and they don't see them. So the people you must be talking about must be the Fox Task Force. They're the ones who see foxes, nobody else.

Ian Townsend: Actually, the Fox Task Force, later called the Fox Eradication Program, has never seen a live fox in Tasmania either.

What the fox program has produced are four already-dead foxes and a skull provided by the public, a DNA sample found in a chicken coop, and two sets of paw prints. These all have detailed stories behind them, and on the Background Briefing website there's a link to what the Fox Eradication Program says about them, as well as a link to what the new scientific review is disputing.

The only fox event that people agree happened was in 1998, when a lone fox walked off a boat at Burnie. It escaped, but being outside the fox breeding season, it was unlikely to have bred or even lived long. Foxes live only three to five years in the wild. It made news though, and was followed by a rash of sightings.

The Fox Eradication Program, now part of the Tasmanian Government's Invasive Species unit, still receives and investigates fox sightings, and rates them for quality from poor to excellent. The sightings—thousands since 1998—have convinced many people that foxes must be in Tasmania.

Peter McGlone from the Tasmanian Conservation Trust says there've been so many sightings, they can't all be wrong.

Peter McGlone: In the case of two carcasses that have been found, you could imagine, well, maybe that was, you know, we haven't found any more carcasses since, maybe that was false evidence. With the sightings, there is a ranking that's placed on all sightings based on a whole lot of criteria about whether it was good daylight, how long you saw it, how far you were from it, what characteristics you could describe without being prompted, all these things are done, and there's scores and scores of very high quality sightings over the last decade or so, including people that I've met who I totally trust as being not just good at observation but very unbiased.

Ian Townsend: But sightings are notoriously unreliable.

The new scientific review of the fox program, led by Clive Marks, has looked at the sightings, and found they peak after media reports.

Clive Marks: When a claim of physical evidence of a fox being identified was advertised in the media we saw a spike or a cluster in sightings around that particular event. So there were two things that drove the sightings: the anecdotal reports, the amount of media, and then the claim that there was convincing evidence of a fox based upon so-called physical evidence. Now, the other interesting factor was of course the decline in fox sightings that was mistaken to be indicative of the efficacy of baiting was only really a decline in media intensity. Annually, the media intensity, as it built until 2009/2010, so did fox sightings.

Ian Townsend: 2006 was a big year for foxes in the media and sightings soared. The fox program's initial funding was coming to an end, and the Invasive Animals Cooperative Research Centre in Canberra published a review of the program and concluded that foxes were still running wild across Tasmania.

This was one of the television news items at the time:

Journalist: It's time for Tasmanians to get serious about fox eradication. That's the message from a team of experts whose new report has found overwhelming evidence of foxes in the state. They say it's time to stop doubting the veracity of recent sightings and get on with wiping them out.

Sally Dixon: There have been more than 1,000 fox sightings in Tasmania over the past eight years. But many have been dismissed as hoaxes. A Canberra based research team has spent 12 months reviewing the State's fox program and says there's no doubt the animals are here.

Tony Peacock, Invasive Animals Cooperative Research Centre: Not just sightings, that's actual bodies, DNA tests from blood and from scats. So anyone that denies there are foxes there, you've got to question why the hell they're doing it.

Ian Townsend: The study by that Canberra research team concluded that 'an unknown number of foxes have been deliberately and/or accidentally introduced to Tasmania since 1998' and they or their progeny were living in the wild. It recommended the use of a DNA test to monitor foxes by looking at fox poo, or what are called scats.

In 2005, a single fox scat had been found at Conara in the Tasmanian midlands. That scat had fox DNA in it, and a new type of fox hunt was on.

One of the advisors to the program, Professor Stephen Sarre from the University of Canberra, had developed a method of testing predator scats for fox DNA. Professor Sarre then used that test to run a survey of scats across Tasmania in pre-determined sites.

Stephen Sarre: So what we did in that survey was collect all predator scats that we encountered. But the primary goal of that survey was to detect any evidence of foxes through DNA in the scats, so that was the primary purpose of the original survey.

Ian Townsend: By late 2012, nearly 10,000 scats had been collected across the state, and 56 were said to be fox–positive; in other words, there was fox DNA in them.

It seemed conclusive. Based on these fox-positive scats, as well as four carcasses and other items, Stephen Sarre published a paper in 2012 saying that foxes were widespread in Tasmania.

But the scientific team that's now reviewing the fox program is disputing that as well. Leading that new review is Clive Marks.

Clive Marks: What we're interested in defining is the existence of an extant, living fox population. So we can't rely upon assumptions or rely upon anecdotal evidence, or rely upon the provision of materials from someone else, we need empirical data to make the case. And that's why the scat DNA data was the most convincing, because it was indeed empirical data. And that's why it's quite significant, if you look at that data and you find that there is a potential for false positives, but there is also no indication that the data that's been gathered is from a fox population and there are many indications that it fits an explanation which has more to do with false positives then foxes.

Ian Townsend: Clive Marks is saying is that there's a high probability that these fox-positive scats are mistakes.

Criminal cases have shown DNA testing can be flawed. The survey test developed by Stephen Sarre was based on mitochondrial DNA, and in 2007 a paper was published saying this test was accurate and reliable.

Clive Marks and his team re-ran that test using a laboratory in Portugal that specialises in mitochondrial DNA and wildlife surveys.

Clive Marks: What the laboratory reported was that there was a great potential for error or false positives, type 1 error by another name, where the scat DNA assay or one of them that had been used by the eradication program failed to adequately discriminate fox DNA from common prey species, an endemic predator, two common species of domestic livestock for instance.

Ian Townsend: In other words, the mitochondrial DNA test used initially to detect fox scats could also identify rabbits and even cattle as foxes. The pattern of the scats across Tasmania also raised eyebrows. One scat was found alone on an island three kilometres offshore.

One of the new papers challenging that DNA test has only just appeared online, and I caught up with Stephen Sarre again when he'd had a chance to read it. He was on a mobile phone in the Tasmanian midlands on a new scat survey.

Stephen Sarre: You know, I don't think it's disputing it. What it's saying is that if you apply a PCR amplification to tissue, that there's a risk that you will amplify DNA from non-target species. Well, that's not new, we've known that always, and I think the important thing is that we run a sequential test.

Ian Townsend: We're talking about a test in two stages here. The first is looking at the mitochondrial DNA to see if it looks like a fox. The second step is the more specific DNA sequencing test, to show that it is fox DNA. However, both those tests together still have the potential for false positives. In other words, there's the potential to mistake something else for the scat of a wild fox.

Stephen Sarre says the likelihood of false positives is extremely low. As few as four in 1,000 scats tested might be a false positive. Remember, nearly 10,000 scats were collected, and 56 show fox DNA.

Stephen Sarre: It's 0.4 of one percent, so four in 1,000 could by chance be false.

Ian Townsend: Well, if you've got 10,000 that's 40 scats, that's getting up towards your range of fox-positive scats confirmed with sequencing, isn't it?

Stephen Sarre: Yes, that would be true, except that we think the number is probably a lot lower than four in 1,000.

Ian Townsend: But the 56 fox-positive scats in your test would come within the range of false positives, wouldn't it?

Stephen Sarre: Well, it's right at the upper end, yeah. So there is a possibility that any of those scats are a false positive, but more testing is needed to get a really precise idea of that.

Ian Townsend: But you'd have to think that potentially all those 56 scats, they fall within that range, they could be false positives.

Stephen Sarre: There is a possibility of that. On the basis of the evidence we have so far, I think that's very unlikely.

Ian Townsend: It was also the distribution of fox-positive scats that concerned Clive Marks. One was found on Bruny Island off the Tasmanian coast. The distribution of scats doesn't match what you'd expect to find from living foxes. Foxes poo six to eight times a day and mark their territories with their scats. When vixens breed they stay near dens for months. If you had a living and breeding fox population, you'd expect to find scats in clusters, not singly, scattered randomly about the state many kilometres apart over many years.

Clive Marks says the random distribution of fox-positive scats is also an indicator of false positives.

Clive Marks: And this isn't an opinion, this is based upon empirical analysis, there's no doubt at all that these data fit false positives better then they fit the existence of a fox population.

Ian Townsend: The complicating thing about this explanation is that if the scats don't match fox behaviour and yet do have fox DNA in them, how did the fox DNA get there?

Since 2005, the Fox Eradication Program has imported more than 1,000 fox scats to train their sniffer dogs, and for other research. We're talking about DNA tests here that are highly sensitive. Miniscule amounts of fox DNA can be passed from hand to scat to hand again. Hygiene's crucial, especially when the teams handling scats for research and training are the same teams looking for wild foxes. At least two scats that tested as fox-positive in the survey—in other words, they were sequenced and found to have fox DNA in them—were later removed from the survey.

Stephen Sarre: I think there's probably…there were two that there was some doubt over the origin of the scats and they were excluded.

Ian Townsend: What do what you mean 'origin'?

Stephen Sarre: Some doubt from the department who decided that they felt there was some doubt about the origin of the scats. That's something you'd have to talk to the department about, I don't know to be honest.

Ian Townsend: We've tried for more than a month to speak to someone from the Fox Eradication Program that's now part of the Invasive Species branch of the Tasmanian Government. We've been told no-one's available.

Contamination is always a risk in DNA testing. Fox carcases and skins have in the past been routinely brought into the State. The Fox Eradication Program had stuffed foxes in its offices.

Background Briefing spoke to a former field worker with the fox program who wanted to remain anonymous, but he described his concerns about contamination.

Fox Eradication Program field worker: The office was festooned with fox pelts, fox bones, stuffed foxes, and it would seem to me if you had fox material in an office and the people who were responsible for collecting that alleged fox scat were moving from that office full of fox parts to collect fox scat, that there must be some potential for contamination there.

Ian Townsend: Back in Canberra, I asked Stephen Sarre how confident he was that scats hadn't been contaminated. After all, fewer than six scats in 1,000 were showing fox DNA.

Stephen Sarre: I think the collection methods have been really well-defined and well-executed, as far as I can see.

Ian Townsend: But here's that former member of the fox team describing what happened during one research project.

Fox Eradication Program field worker: One of the people I was working with pulled the scat apart, withdrew a little microchip sensor like the size of a grain of rice and swallowed it, and thought it was quite comical and pretty funny. I tried to explain that this would have implications for an expensive scientific research program and it probably threw the whole study out.

Ian Townsend: There's also a question about the reliability of the four fox carcases and the skull, for instance, used as evidence of living foxes in Tasmania.

They were included, along with the scats, in Stephen Sarre's scientific paper that said foxes were widespread. Based on the subsequent review, I suggested to Stephen Sarre that the carcasses and skull weren't really good evidence.

Stephen Sarre: I guess I beg to differ. There are strong road kill evidence there. I'm not sure exactly what the point of revisiting that in the sense of 'was there a hoax at some point'.

Ian Townsend: Well, as part of your paper you presented the scats plus the nine other pieces of physical evidence so, you know…and the quality of evidence does matter. Did you see the evidence though?

Stephen Sarre: There's doubt on every piece of evidence. I mean, most of it we cannot put a probability on what the doubt is around it.

Ian Townsend: The problem with the carcasses and the skull is that they were all reported by members of the public and were all moved before they were examined. The stories about where they came from changed. Muddying the issue is a tradition of hoaxing in Tasmania.

As we heard, a team of scientists has just reviewed the evidence and rated most of it unreliable. They're publishing their findings in the Wildlife Society Bulletin, and there's a link on the Background Briefing website.

A co-author of that paper is veterinary pathologist Dr David Obendorf

David Obendorf: All that information has been shown to be to have very questionable authenticity, and the provenance of those carcasses is the problem that nobody can actually demonstrate that there is any linkage of those animals to the landscape in which they've been found.

Ian Townsend: But they were found in Tasmania. How did they get here?

David Obendorf: Well, how did they get here is the big problem, that we know that the borders are flaky, that people can bring things in. The difficulty that the Government had in 2009/2010 was that there was clear evidence that people were bringing in carcasses or fox products like green pelts that were being requested to be tanned or whole carcasses that were being asked to be taxidermied by freeze-drying, and these animals were going through, passing the border barrier quarantine and coming to Tasmania.

Ian Townsend: The Fox Eradication Program's former biologist Nick Mooney is angry that people use this to doubt the existence of foxes in Tasmania.

Nick Mooney: A lot of people just glibly dismiss stuff that doesn't suit their frame of mind.

Ian Townsend: You'd silence any critics, wouldn't you, if you could prove that a dead fox beside the road was…

Nick Mooney: No, how would you prove it? There'd be people who would just say we planted it there.

Ian Townsend: There might be scats nearby.

Nick Mooney: Well, people just say you've planted them there.

Ian Townsend: So you think people are that cynical?

Nick Mooney: Absolutely, we've got plenty of stuff like that from some of the people you've interviewed that just keep moving the goalposts, and if you take the conspiracy card and say, 'Well, that might be the case except you guys planted it anyway', which is what has often been accused, well, that's incredibly lazy thinking, and it means you can win any argument, you just say people made up. And I'm afraid there's an awful lot of that in Tasmania.

Ian Townsend: I get the feeling that they are operating in good faith, they're not being cynical for the sake of it.

Nick Mooney: I don't share that entirely.

Ian Townsend: Why is that?

Nick Mooney: I think there's an element of scuttlebutt here and some people enjoy the intellectual warfare, let's put it like that.

Ian Townsend: The intellectual warfare is all about the evidence. Most people associated with the fox program say even if you dismiss the evidence, it's not been worth taking any risk, so destructive would foxes be to Tasmanian wildlife.

Here's Peter McGlone from the Tasmanian Conservation Trust:

Peter McGlone: And so a lot of people can't seem to ask the question, well, should we wait until there's a lot of foxes and then try and eradicate them? They never seem to want to ask that question and if they did they would obviously say of course we don't want to wait until there's a lot of foxes and then try to eradicate them, we should try and eradicate them early on when there's few of them. And if they there's few of them in a big landmass that's ideal for foxes it's going to be hard to sight them, it's going to be even harder to find them, find physical evidence.

Ian Townsend: When the baiting program began more than a decade ago, it was believed foxes had been released around the state. With that story now discredited, and major question marks over the other evidence of foxes, Clive Marks says there's no need to keep using the precautionary principle.

Clive Marks: The trigger for the precautionary principle requires that there is a cogent argument or there is evidence to suggest that the problem exists. When you use anecdotal information, when you use information which is not empirical data, you risk triggering the precautionary principle for no good reason. There must be a scientific or evidence-based reason to trigger the precautionary principle, and this is one of the major lessons from the program.

Ian Townsend: No physical evidence at all for foxes has turned up since 2011. Without a live fox to show for a decade-long eradication program, the existence of foxes in Tasmania has become theoretical even to the people associated with the program.

I asked the former spokesman of the Fox Eradication Program, Nick Mooney, if he was worried about a backlash over the amount of money spent.

Nick Mooney: There is the potential for that sort criticism or image for some people, and a whole lot of other people though I suggest would say good on you for not taking a risk. Because a lot of people would understand that by the time you had enough evidence to satisfy everyone it'd be too late to do anything and you can't wait that long. In the end, in 20 years or 30 years or whatever, people will ask, did you get rid of foxes. They won't ask how much you spent.

Ian Townsend: Background Briefing sought a response from the Tasmania Government about the millions of dollars spent of the Fox Eradication Program for no result. The Minister for Primary Industries, Jeremy Rockliff, declined to be interviewed, but his office released a statement saying that the new Liberal Government is concerned about how much money was spent on fox eradication at the expense of other threats. The Government's just announced a new Biosecurity Division to look more widely at a range of threats and to protect Tasmania's pest-free reputation.

Veterinary pathologist David Obendorf agrees about Tasmania's reputation, but says it's a different kind of reputation that's already been damaged.

David Obendorf: It's really not doing justice to Tasmania's ability to take charge of an issue which is really important, and particularly if they are getting Commonwealth funding on the back of it, that there should have been very, very rigorous oversight. And I think we've inherited a problem out of a failure of due diligence.

Ian Townsend: Background Briefing's co-ordinating producer is Linda McGinness, research by Anna Whitfeld, technical production by Russell Stapleton, the executive producer is Chris Bullock, and I'm Ian Townsend.