The life-long Liberal Party member owes the three high points in his career to federal Labor Governments.

Here's how that unpacks.

Back in the day, he was ACT Chief Minister - Bob Hawke had forced the creation of the ACT Legislative Assembly; later, Humphries was an ACT senator - Gough Whitlam had given the ACT two senators; and now Humphries is deputy president of the Administrative Appeals Tribunal – Whitlam created that body.

And here's another titbit about the former ACT Liberal Party senator – he became a lawyer so he could enter politics.

Today, after 30 years in the tough political arena, he is again reading law books, as he hears matters coming before the tribunal and writes judgements.

It's a powerful, judge-like position.

You may go to the tribunal to appeal against a decision by the federal government department or agency or perhaps Comcare on a workers compensation case.

"If that's knocked back, that's when you come to the AAT, so it's always the third bite of the cherry [but] it is your last bite of the cherry on a question of fact," Humphries says.

When the tribunal hands down its decision, a party can appeal to the Federal Court on a question of law but the tribunal's decisions on questions of fact are final.

"There's a sense that you've got enormous power to fix what is very often a very significant event in someone's life," he says.

He didn't predict he'd be sitting on a bench at this stage of his life, facing lawyers and barristers, hearing cases, researching precedents, writing judgements.

Sipping a coffee at Manuka on the Queen's Birthday holiday, he muses how his life has changed – for the better.

As a politician, he was working seven days a week, mostly from early morning into the evenings.

Now the workload remains high but his working life is less manic and more family friendly.

"The pressure of making the right decision is still there," he says.

"In politics you want to make sure you get your decision right so you can live with it, both electorally and in terms of, if you're a minister, how your area of responsibility is carried forward in the future.

"That's still there, in the sense you're very conscious that some poor soul has come before you seeking justice against a government department and you've got to assess whether the government department acted correctly or not, it's up to your judgement on that particular government department.

"That sense of responsibility for a just decision is similar to the responsibility in politics and particularly as a minister.

"In terms of the time it takes to do that, the pressure is certainly less, if only because in politics every hour of your day is sucked up into some kind of committee, ceremonial activity or meeting opportunity or community engagement which you have to be part of.

"It is relentless pressure, every night and every weekend, so not being on that treadmill is a pleasant relief.

"I'd forgotten how much of a time heavy routine that had become.

"For my family in particular, they're still not quite used to coming down in the morning and seeing me there and having breakfast, rather than being off somewhere first thing."

Humphries was elected to the ACT's first parliament in 1989, following the granting of self-government, and served for 14 years.

He was a minister in Trevor Kaine's Liberal administration, followed by a period as Opposition Leader, then a minister again in the Kate Carnell administration.

He became Chief Minister in 2000 when Carnell resigned, but retained the treasury portfolio.

He was Opposition Leader again after the Liberals lost the 2001 election and Labor's Jon Stanhope formed government with the support of the ACT Greens and Democrats.

Humphries filled a Senate casual vacancy in early 2003 when long-serving ACT Liberal senator Margaret Reid resigned, becoming the 500th person to enter the Senate.

After another decade in politics, he lost Liberal Party preselection to former ACT Opposition Leader Zed Seselja, and left the Senate at the 2013 election.

He was entitled to a parliamentary pension of about $80,000 a year but looked around for a job in the private sector.

Humphries was hired as a lobbyist, working between Canberra and Sydney, and also became a columnist for The Canberra Times.

Some of his colleagues in the Abbott administration felt badly about his involuntary departure.

"My colleagues had been knocking on my door throughout 2014 with offers of various sorts, they felt some sort of sense of responsibility to see I was looked after so I did have a number of offers made," he says.

"Initially I said no – I'd been working for governments one way or the other for close on 30 years and wanted to get off that treadmill for a while and see how I would go working in the private sector.

"I've spent years lecturing everyone about how important the private sector is, here's my chance to live that and I don't want to mess it up."

Was he offered an overseas post? "Yes ... that's all I can say, sorry."

So the offer of the tribunal did not come out of the blue but had the added attraction of being part of the legal system.

He was due to go on holiday in Europe with his wife, as the appointment was about to be announced.

"I realised I would have to spend some of that holiday brushing up on the law so I took a couple of text books with me and ploughed through them on the trains."

How is the transition going, from politician to consultant to tribunal member?

As deputy president, he is responsible for the reasonably small registry making consistent and timely decisions.

He works with a full time senior member, four part-time members and registry staff.

Registrars conduct conciliation or mediation sessions with parties coming before the tribunal to attempt to resolve the conflict.

That reduces the number of cases proceeding to a hearing, but applicants can insist on a hearing, no matter how weak their case.

"There are some matters you can tick and flick quite quickly, for example some people come forward claiming a pension and their problem is they don't understand how the legislation works," Humphries says.

"They might be sick and say, I should be entitled to claim a disability support pension but don't realise the legislation is very prescriptive about what they have to do and they just don't satisfy those requirements.

"It would be quite easy to say no case is made out. You have to carefully go through the evidence, which they often haven't done themselves, to assess on what basis the government has made the decisions.

"Some people get quite obsessed about the need for justice here and they'll often take a matter all the way to the AAT and occasionally beyond because they have a powerful sense they need to be vindicated.

"A party that has an absolute conviction they are right and the government is wrong, can be told by a registrar they should look at it in a different way but they might refuse to do that. The registrar can't say, sorry, you can't go to the tribunal.

"They can try to educate them about what's required and maybe give them a hint they might not be able to succeed but they will always point them into the tribunal if they're not satisfied with that process."

Life's revolving door bemuses Humphries.

"I wouldn't have predicted [this appointment] at all," he says. "I wouldn't have said I was an outstanding lawyer because I never wanted to make it my career.

"I had always seen it as a vehicle towards getting into politics, never as an end in itself. So coming back all these years later and suddenly finding myself back in the law, is a funny type of feeling."

This month Humphries handed down a judgement against a plaintiff who suffered a stroke at work at the Australian Taxation Office in 2003.

George Stacey subsequently gave up work in 2004 and Comcare accepted liability for "unspecified cerebrovascular disease", in effect, a stroke.

For a decade after the incident, Comcare was meeting a range of his medical and pharmaceutical costs.

However, in early 2014, Comcare stopped payments for three drugs, for wound dressings and for visits to a haematologist, on the basis these treatments were not related to his compensable condition. Other costs, such as those related to his visits to his GP, Dr Shroot, have continued to be met by Comcare.

Stacey sought reconsideration of the determinations but they were affirmed in March 2014. He submitted the items were "essential for the maintenance of my health and to prevent me having a further stroke", propositions to which both doctors giving evidence agreed.

After a hearing, Humphries found Comcare was not liable for costs relating to Stacey's essential thrombocythaemia, a condition in which the body produces too many blood platelets, nor for costs relating to the prevention of future strokes.

"I note that the cost of drugs Mr Stacey claimed for was a modest $216 per year," Humphries wrote in his judgement, available on the tribunal's website.

"Mr Stacey is 76 years of age and quite unwell. Even if he lives for another 15 years, it is doubtful that Comcare will recover the cost of this litigation with its victory today. One wonders whether a better outcome might not have been found."

On July 1, the Social Security Appeals Tribunal and the Migration Review Tribunal – Refugee Review Tribunal will be absorbed into the existing Administrative Appeals Tribunal, a move described by the federal government as the biggest shake-up of administrative law in 40 years.

The revamped AAT will hear challenges to government decisions on visa applications and social security benefits, in addition to its existing jurisdiction over workers compensation, disability support, freedom of information requests and veterans' entitlements, and is expected to adjudicate 40,000 applications around Australia every year.

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