With his death, Australia lost a man whose selfless dedication to public service and progressive governance is becoming all too rare.

Former independent MP for New England, Tony Windsor called him an outstanding senior public servant to his country: "Paul Barratt was the epitome of intellectual integrity in his work for various governments over many years."

Former Greens leader Christine Milne described him as thoughtful and courageous, and a powerful advocate for war powers reform and refugee justice.

"He served our nation with distinction."

Born in regional NSW, Paul attended The Armidale School, before graduating from the University of New England with an honours degree in physics. He moved to Canberra soon after and was employed in the Joint Investigation Bureau in the Defence Department. With a razor-sharp mind, Paul quickly gained a reputation for being adaptable and quick off the mark.

He rose in the Commonwealth Public Service to hold senior appointments in the departments of Treasury; Minerals and Energy; National Resources; and Foreign Affairs and Trade; culminating in Defence, where as secretary between 1998-99 he was unafraid to tell ministers what he thought.

Paul was dismissed 18 months into his five-year contract after then-defence minister John Moore said he "had lost trust and confidence" in Paul's abilities to perform his duties.

As political reporter Katharine Murphy later wrote about the affair: "Barratt was sacked ... because he and the then-defence minister did not get along."

A number of respected departmental secretaries have since been dismissed, with the Abbott government sacking heads of departments. Critics expressed concern that such moves damaged the ability of the public service to give frank and fearless advice.

Paul took legal action but his appeal was dismissed by the Full Bench of the Federal Court. He later told ABC Radio's PM program that it was a "complete derogation of any sensible principle of public administration ... that one of the most senior officers in the service of the Commonwealth can be removed from office simply on the basis of the minister reciting a formula to the effect that 'I have no confidence in the secretary'."

Paul went on to a stellar career in business, consulting and research, always with the aim of improving Australian society and expanding Australia's role in the world.

He advised successive governments on uranium mining, the Multifunction Polis, the bridge Australia built over the Mekong River, and much else. Paul was Australia's special trade representative for North Asia in the late 1980s, and executive director of the Business Council of Australia for four years in the early 1990s. For his service to public administration, public policy development, business and international trade he was made an Officer of the Order of Australia in 1999.

Paul also chaired Australian Aerospace and Innovations from 2006 to 2010, and was director of AADI Defence P/L from 2010.

In 2012, Paul joined with a cross-section of Australians to form the Campaign for an Iraq War Inquiry, which called for an investigation in Australia, like that headed by Sir John Chilcot in the UK, into the Iraq war. Former prime minister Malcolm Fraser was a strong supporter from the very start, and Paul the founding president. In 2015, the movement became Australians for War Powers Reform. Its non-partisan campaign sought popular and political support for legislative change to require a debate and a vote in Parliament before a prime minister can dispatch the Australian Defence Force to war.

Paul's persistence and influence as president of AWPR helped build support for the campaign. A poll conducted by Roy Morgan in 2020 recorded 83 per cent support among Australians for this legislative change. The most recent poll, commissioned by Mike Smith, a journalist and former Howard government adviser, and conducted by market research firm The Digital Edge found support was even higher, at 87 per cent.

Returning to Armidale as Principal of CEO Collegiate P/L, he became a director of the UNE Foundation, and an adjunct professor in the School of the Humanities, Arts and Social Sciences at the University of New England. He actively supported the New England Regional Art Museum, particularly its Howard Hinton collection of Australian art from the 1880s-1940s. He travelled regularly to take summer courses at Cambridge University, and to attend Sibelius festivals in Finland.

He also found time to present seminars at UNE on Australia's defence policy, the corrosion of public service integrity, post-traumatic stress disorder in first responders, and the strategic implications of COVID-19 for Australia. With the arrival of Ezidi (Yazidi) refugees in Armidale, he initiated and led a Regional Employment Agriculture Project to help them develop skills for living in their new home.

As a director of Australia 21 from 2001, Paul led the independent think tank in its evidence-based research "for the public good". This resulted in a major report published last year, Shaping the Human Future, which appeared just as Australia was faced with the need to devise innovative public policy following natural disasters and the pandemic.

Since the news of Paul's passing became known, social media has been filled with tributes from a wide variety of people, including politicians, journalists, diplomats, activists and fellow social media users.

The former federal Labor MP and former United Nations lawyer, Melissa Parke, said: "Vale Paul Barratt, an Australian of enormous integrity, courage and the determination to make this country live up to its potential as a force for good in the world."

He is survived by his family: Tom, Anna, Pauline, Oscar and dearest friend Angel.