In June 2015, Chancellor Gareth Evans wrote to the then vice-chancellor Ian Young to discuss both the school's struggling budget and concerns about the health of Professor Tregear, who had arrived at the school to right the ship after brutal funding cuts in 2012.

Three years later, more cuts were on the table to curb the school's ballooning debt - including axing its celebrated but expensive one-on-one performance teaching and absorbing the institution into a combined school of art and music.

"The budgetary situation is dire, even if performance is phased out," Professor Evans wrote in 2015.

"The [university] council ... is very clear that however much we might wish we had never bequeathed them, both music and art need to be presented in some form at ANU."

Professor Evans stressed he was not saying "there had been any formal decision by the council that the school, was to be preserved in some form".

While management had then recently announced a "package to guarantee the future of the school", Professor Young suggested the university should consider using Tregear's expected departure as a "trigger to consider whether we continue with a School of Music".

If the council agreed, he volunteered to "clear the deck" for the incoming vice-chancellor Brian Schmidt - but noted the chancellor's directive that bad press, such as the kind likely to arise from the closure of the school, was to be avoided.

The correspondence was revealed this month as the Administrative Appeals Tribunal handed down its long-awaited decision on Professor Tregear's battle for workplace injury compensation.

The former department head claimed his mental health had deteriorated under toxic working conditions at the school and he had no choice but to leave the ANU in August 2015, but his Comcare claim was later overturned by the insurer around the time he signed his exit agreement.

In the year leading up to his departure, Professor Tregear and other academics complained of crippling staff shortages and low morale. Comcare was itself investigating a suite of complaints at the school as it continued to haemorrhage staff.

Diagnosed with anxiety and depression in December 2014, Professor Tregear became the fifth staff member at the school to take stress leave that semester.

In May 2015, he returned to what he called a school in crisis and claimed to have been cut off from the department's budget. A number of staff remained on leave or secondment, despite repeated requests from the school for help on the ground.

Professor Tregear said he became increasingly uneasy he couldn't keep staff safe under such working conditions and had been "set up to fail" even as he tried to turn the school around.

More than a year after public hearings into the matter were held, tribunal deputy president Greg Melick this month found Professor Tregear was still incapacitated when Comcare cut off his compensation payments in 2015, as evidenced by medical professionals who saw his conditon as the result of his working conditions. The matter has now been sent back to the insurer for negotiation.

"I'm relieved more than anything," Professor Tregear said on Monday.

"But that evidence in the judgment shows my instinct was right, there were decisions being made [about the school] higher up that we knew nothing about. I knew nothing about the budget. That's going to put any manager in an impossible situation.

"I was effectively being gaslighted."

The tribunal did not make a finding on allegations the university failed to hand over a key medical report into Professor Tregear's condition to Comcare or that a senior ANU official provided incorrect staffing figures.

But Mr Melick did accept the university's assertion that a job posting appearing to advertise Professor Tregear's position while he was still on leave was a mistake, though a poorly handled one. He also accepted the ANU's claim security guards sent to the school in 2015 were not there to remove Professor Tregear from the building, as the academic believed.

In his 76-page judgement, Mr Melick noted the university had also funded the head of school's initial rehabilitation.

It is unclear if Comcare or the ANU, which began self-insurance in 2018, will negotiate the costs owed. The university was seeking legal advice on Monday as it reviewed the judgment.

In 2016, a review of the school led by former public service commissioner Andrew Podger backed many of Professor Tregear's claims, describing a concerning culture of stress and distrust and calling for an overhaul of its governance and financial management.

A spokeswoman said on Monday the ANU decided, in response to that review, to invest in the future of the school with a funding injection of $12.5 million over five years.

"Since then, student enrolments have more than doubled and the school has set a clear direction to offer a 21st-century music education that innovates even as it values traditional music practice," she said.

But some staff have since bemoaned the seemingly slow adoption of recommendations from the Podger Review.

In 2015, Professor Evans noted incoming vice-chancellor Professor Schmidt had insisted music have a place on campus in some form and had requested briefings on any major decisions at the school.

Know more? Get in touch: sherryn.groch@canberratimes.com.au