Having so aptly diagnosed the problem - a lack of board accountability to communities - it is a matter of great puzzlement to many observers that Henry then went on to demonstrate such scant personal deference to the royal commission process. It’s a failure upon which Henry, one of Australia’s most decorated public servants, has spent much time reflecting on since his appearance last November. “I can't tell you how many times I've re-lived that appearance,” a markedly more humble and somewhat weary-looking Henry told the ABC’s Leigh Sales on Thursday night's 7.30, following the shock announcement that both he and NAB’s CEO Andrew Thorburn would depart the bank in the wake of a damning review of both men in Commissioner Kenneth Hayne's final report. “I really should have performed quite differently. I should have been much more open." Loading Replay Replay video Play video Play video It may yet prove comfort to Henry - who will stay on as chair until a replacement CEO is found - that his central message about board accountability has been so vividly delivered home; if not by his words, but by his ultimate fate, as the biggest scalp so far of the royal commission.

'The smartest guy in the room' Loading It’s the end of a chapter in what been as been an illustrious career for Henry, who is described variously by friends and former colleagues as "the smartest guy in the room" and “arrogant”, but also "warm" and “shy”. A Treasury contemporary of Henry's from the 1980s recalls him as “stunningly smart”. “He was a hero from day one. He stood out from the crowd.” But intelligence can be a curse.

“Ken generally always has been the smartest guy in the room and for that person, it’s hard sometimes not to be arrogant - for want of a better description," says the same former Treasury official, who asked not to be named. "People are forever wasting your time. People are forever not understanding things that you understand. [So] when you see him in the royal commission, mumbling away and people don’t seem to understand what he’s saying - it’s classic Ken.” A meticulous obsession with detail is also classic Henry. When the Herald and Age ring to invite further comment on the tumultuous week, Henry demurs. But not before insisting on rephrasing his original question put to Orr. "It should perhaps be better phrased as 'to whom do boards owe their accountability'," he muses, in a rearrangement of his original "to whom should boards be accountable', the necessity for which might stump a lesser mind. Nature man Kenneth Ross Henry lived his first five years on a dairy farm on the mid-north coast of NSW, near Taree. To this day, he continues to seek regular solace in the natural environment and credits his early exposure to rural life as the driving force behind his passion for wildlife and conservation.

An outspoken opponent of kangaroo culls and Japanese whaling, Henry famously disappeared in mid-2008 for a period of extended leave to care for endangered northern hairy-nosed wombats in Queensland. Loading After attaining an honours degree from the University of NSW, Henry lectured and studied for his PhD at the University of Canterbury in New Zealand, before applying to the Australian Treasury in 1984. He was immediately thrust into the tax policy melee, working on the Hawke government's tax white paper, which would develop the infamous “Option C” for a broad-based consumption tax – effectively the GST we have today - that was ultimately rejected by the 1985 tax summit. Soon after his arrival at Treasury, Henry was seconded to the office of then treasurer Paul Keating, where he earned the ire of some Liberals by using his considerable intellect to help pick apart the arguments of Liberal leader John Hewson’s “Fightback” package, which Hewson took to the 1993 election.

The centrepiece of the package? Essentially the same broad-based consumption tax which Henry had helped develop for Keating. In yet another twist in the GST story, Henry would go on to steward the idea into reality, as head of the Howard and Costello government's GST implementation taskforce. Henry's performance in the "GST bunker" impressed Howard and Costello sufficiently for them to appoint him to the plum job of secretary of Treasury in 2001 - a job he held until 2011 and one which also gave him a seat on the board of the Reserve Bank for that decade. [Treasurer Peter] Costello ... found him very condescending - Ken acted like he was the only one in the room with a brain Howard government staffer Henry would fall foul of the Coalition again in the lead up to the 2007 election, when a speech he made to Treasury staff was leaked to The Australian Financial Review. In it, Henry reflected on the Howard government’s announced $10 billion funding package for the Murray Darling and warned of policy making ahead of the election that was “frankly, bad”. One Howard government staffer recalls: “People started calling him 'Red Ken'. Relations weren't good before that but they got a lot worse. [Treasurer Peter] Costello couldn't stand Henry. Found him very condescending - Ken acted like he was the only one in the room with a brain."

Ironic, to some, coming from the famously confident Costello? "Yes ... but I guess it shows he can out-patronise anyone". Still, Henry was awarded the Companion of the Order of Australia in 2007 under the Coalition, with his citation mentioning his "care for native wildlife." 'Go early, go hard, go households' The newly-elected Rudd government and its treasurer, Wayne Swan, would soon come to lean heavily on the expertise of Treasury secretary Henry when the global financial crisis threatened to engulf the Australian economy. Having witnessed first hand the failure of the Keating government to react quickly enough to the early 1990s recession "we had to have", it was Henry who, after the collapse of Lehman Brothers in late 2008, urged Rudd and Swan to “go early, go hard and go households”, unleashing huge stimulus packages, including cash cheques for households.

Rudd has praised Henry as a "source of sage and courageous advice" during that tumultuous period. "Yes he botched his testimony to the royal commission," writes Rudd in today's Herald and Age. "But before the national zeitgeist turns Henry into a national scapegoat for the ills of an entire industry, the country should reflect for a moment on where Australia might be today were it not for Henry’s critical role a decade ago." Loading Former Reserve Bank board member and economist John Edwards, who also served in treasurer Keating's office, says Henry is rightly due a large portion of the credit for Australia's response to the global financial crisis, alongside the government and Reserve Bank’s rapid-fire interest rate cuts. “Ken has really made huge contributions to Australian public life, to the quality of this country, over many years,” says Edwards. On a personal note, Edwards describes Henry as: "Very, very personable. Rather quiet - I would say almost a rather shy person. People like him. He’s quite amusing.”

One of the most enduring images of Henry, however, is of him standing, stony-faced and silent, in the corner of a Parliamentary Committee room as Rudd and Swan released the findings of his Tax Review in 2010. The duo were announcing they would not adopt the vast bulk of Henry's 138 recommendations - perhaps explaining his stormy demeanour. Loading Only one of Henry's ideas – a proposal to reform mining taxation – found true favour in Rudd's mind. And it would ultimately prove his political undoing – a fierce backlash from the mining sector contributing to Rudd's toppling by Julia Gillard. Some observers slate home a portion of the blame for the failure of Rudd's mining tax to Henry's original proposal. A theoretically elegant scheme - in which taxpayers would share miners' windfall gains in good times, but also wear some of their pain in bad times - but an unworkable one in the real world, according to some. After passing on the Treasury reins to his successor Martin Parkinson in early 2011, Henry led the Gillard government’s Asian Century white paper, before moving into his first corporate gig, as a director of Australia's fourth largest bank.

From public servant to private boardroom Henry's elevation to NAB chairman in 2015 occurred at broadly the same time the NAB board was responding to the internal reports of an alleged bribery ring operating across its western Sydney branches - the first sensational bombshell of the royal commission. Along with other banks, NAB was also embroiled in a deepening crisis with regulators over the charging of “fee for no service” for their wealth clients. Board minutes, released as part of the commission's hearings, also reveal the board dealing with an emerging expenses scandal in CEO Andrew Thorburn's office - fresh revelations about which put extra pressure on the pair to depart. Henry’s biggest preoccupation as NAB's chair, however, was an attempt an overhaul executive remuneration. The idea was to shift away from short-term bonuses which may have encouraged NAB executives to delay reporting misconduct.

But Henry's new scheme, which included a $2 million bonus for Thorburn, ultimately received a record protest vote and “first strike” from NAB shareholders last December. Outgoing National Australia Bank CEO Andrew Thorburn speaks to the media outside his home on Thursday. Credit:Eddie Jim Investor ire was also raised by a decision not to hike interest rates in lock-step with other major banks late last year, a move which did little to boost NAB's reputation but cost shareholders an estimated $70 million. By his own standards, Henry said this week that NAB, under his leadership, continued to fall short of customer expectations. Former Treasury colleagues say it would have been a difficult transition, from public servant to private boardroom. “Suddenly the smartest guy in the room is having to do and say things that I suspect drove him internally berserk,” says one, pointing to Henry's decision to speak against the bank levy, which economists generally support.

It was always going to be an uphill battle, says John Hempton, the founder of Bronte Capital and a self-professed friend of Henry. In 2016, Hempton and a UK analyst, Jonathan Tepper, spent time visiting bank branches in western Sydney where they say they uncovered evidence of pervasive mortgage fraud. Loading “I went to have a chat with Dr Henry who took our findings seriously and began the (admittedly difficult) task of improving the National Australia Bank," Hempton wrote on his blog this week. "He was open about the difficulties in doing so, open about the incentives both within the bank and outside the bank and was cognoscente how difficult this was going to be. But he started.” But Hempton is at pains to point out it was not just NAB engaged in dodgy practices. In fact, NAB emerged from their survey as the “least bad of a bad lot” compared to other major banks. As Hempton sees it, an “injustice has been done” in singling out NAB and Henry. "The most honest party at the Royal Commission has paid with their career for their honesty.