MICHAEL McHugh reckons his friend and fellow High Court judge Michael Kirby once had other ambitions.

"I think he might have liked to have become prime minister, but for one reason - his sexuality."

McHugh's account of how Kirby "came out" to the nation's top judges is tinged with sadness - sadness that his friend felt compelled to keep his life with partner Johan van Vloten under wraps for almost 30 years.

He and fellow retired judges Ian Callinan and Mary Gaudron spoke to The Weekend Australian in the lead-up to the announcement this week that Kirby would retire from the bench on February 2, six weeks short of his 70th birthday.

McHugh describes him as "relentless", Callinan offers "indefatigable" and Gaudron settles for "courageous".

In many senses, McHugh has had a ringside seat for Kirby's career. They worked together as barristers and sat together for five years on the NSW Court of Appeal and then nine years on the High Court. Yet McHugh says he "had no idea" Kirby was in a longstanding relationship.

"There were Court of Appeal Christmas parties held at his place and there was never any sign of Johan. I was at a wedding and (the late solicitor) John Marsden was there and came up and started talking about Michael and he said, 'He's had this partner for 30 years'. Frankly, I didn't believe it.

"That was in December (of 1997). I was in New York over Christmas and there was this barrister with a gay background and I asked him and he said, 'Yes, that's right'.

"I made up my mind that when I came back to Australia I was going to speak to him about this because I was bit offended by the fact I had known him for 30 years or longer and he'd never even mentioned him.

"The second day I was back, I went in for the precise purpose of raising this question and quite coincidentally he said 'my friend, Johan' in that context.

"I said: 'Michael, I have known you for over 30 years and that's the first time you have even mentioned Johan's name to me'. He said to me he had read a book over the break about coming out."

Kirby decided he would talk with his then fellow judges - chief justice Gerard Brennan, McHugh, Gaudron, William Gummow, John Toohey (replaced by Ian Callinan in February 1998) and Ken Hayne - before the 1999 Who's Who officially revealed his "status".

"The next week the court went back to Canberra," says McHugh, "and Bill Gummow came round to my chambers on the Tuesday morning and said: 'You won't believe it. I was invited round to Kirby's place last night and Johan was there for dinner'.

"The next night I got an invitation to come round, so I met Johan.

"I think Mary Gaudron was also invited. But there were some people he wouldn't have invited around because he feared the reaction."

Kirby's biographer, Griffith University academic A.J. Brown, believes he would have chosen politics over the law as a career, but feared his progress would be stymied in what were less accepting times.

McHugh agrees: "I think he was very conscious that if he revealed anything about him being gay it would have had a devastating effect.

"I ran into Gareth Evans one day at the airport in Canberra - when he was minister for foreign affairs and at that stage Kirby was on the Court of Appeal - and I said to him: 'Why hasn't your government given Michael Kirby some overseas posting? He'd be so good at it'. Evans said to me: 'It's f..king prejudice'. That's all he said, leaving me to my own conclusion about where the prejudice was coming from."

The attorney-general at the time of Kirby's appointment to the High Court in 1996, Michael Lavarch, says there was no mention of Kirby's sexuality in government circles. "I did, however, have a problem with his support for the monarchy."

Kirby replied by email that it was not any reading that made up his mind.

"No. It was not a book. It was the advice of my partner Johan, who said: 'We owe it to the younger generation'. He was correct as usual."

The judge embraced his status as one of Australia's most famous gay men. He visited schools to talk about how it was OK to be homosexual, railed against church attitudes and opened the 2002 Gay Games.

That year he became a political target when Liberal senator Bill Heffernan accused him of improper use of a commonwealth car and "trawling" for under-age male prostitutes. Chief Justice Murray Gleeson claimed there had been a breach of not only parliamentary privilege but "conventions aimed at shoring up judicial independence and impartiality".

The supporting evidence turned out to be a forgery, and Heffernan offered an apology, which the judge accepted. "Out of this sorry episode, Australians should emerge with a heightened respect for the dignity of all minorities," Kirby said.

Kirby also turned his retirement into a statement about gay rights. He let it be known earlier this year that he would be happy to step down if the Government secured passage of same-sex legislation which would allow him to leave his judicial pension to van Vloten. He delivered on his word on Wednesday, after a visit to the Governor-General Quentin Bryce.

McHugh says that "like most successful people there is a degree of vanity there".

"He would like to be remembered for his contribution. It's possible his whole life has been directed towards securing a place in history."

He suggests that once Kirby got to the High Court, he felt that place was secure. "I think that was probably the chief motivating force."

McHugh points to a comment by Harold Glass, the former NSW Court of Appeal judge, that Kirby's public speaking "was his substitute for family life".

"I think that's probably right," says McHugh.

Brown prefers to think of it as a second career, one that has made him Australia's first celebrity judge and one of the nation's most enduring public intellectuals.

He says Kirby "has had to walk a very difficult line in terms of his judicial role".

"There is a lot of healthy debate about how well he, or anyone else, has trod that line."

In recent times, Kirby has complained of feeling isolated on the court presided over by Gleeson from May 1998 until August this year.

He is the biggest outsider in the court's history, offering a minority view in about 40 cent of his cases. He became known as the "the great dissenter".

That he would play on the tag in public forum only disguised the hurt - and eventually led to him lashing out, especially on the court's reluctance to embrace international law. If the globalisation of the economy was possible, why not the law?

Callinan believes the more strident nature of his comments of late reflects "some frustration on his part". McHugh suggests "it grows out of resentment and impulsive statement rather than a studied position".

Gaudron, who sat with Kirby on the court for seven years, says he "had his difficult moments".

"To a certain extent - not absolutely but to a certain extent - the High Court survives on the basis of collegiality and mucking in when you can agree.

Michael was his own person, so you could rarely ask him to write the first judgment. This caused some difficulties."

Kirby has taken solace in his belief that his dissenting views will be embraced by future generations.

He is an admirer of Whitlam government attorney-general and High Court judge Lionel Murphy, who made him the inaugural chairman of the Australian Law Reform Commission in 1975.

Murphy argued against precedent when he considered the outcome unjust. He also frequently cited international law and treaties. And he was adventurous.

In 1977, Murphy found there was an implied freedom of political communication in the Constitution but the court did not agree until 1992.

Kirby would praise Murphy with the words he would insist might one day apply to him. "Powerful ideas simply expressed can work within our legal system to plant their seeds of doubt until in due time the once dissenting view become accepted."

McHugh has his doubts: "I have some problems about accepting the view that history will vindicate him, but people's views change so much".

The most incongruous thing about Kirby is that he is a monarchist. Yet it fits neatly with his respect for pillars of society such as family, church and parliament. He has also emphasised the importance of obligations in his judgments, especially in contract cases.

It is almost as if he distinguishes between those in a position to help themselves and those who can't because of the impediments put before them. Indeed, if Callinan could be described as a radical conservative, then Kirby is the conservative radical.

Regardless of their opinion of Kirby's legacy, they are clearly very fond of the man.

"Courage is his greatest attribute and that's why he has succeeded. He is truly courageous - not always right in my opinion, but that is his greatest asset," says Gaudron.

She says he also "genuinely thinks - in my view naively - the best of his fellow citizens, his fellow human beings".

"That not why I think he has succeeded. He has succeeded in spite of that."

Gaudron, who is supporting Kirby's likely appointment to a new UN tribunal aimed at weeding out corruption among UN staff, says he "doesn't rush to judgment about people".

"Issues yes, but people no."

Callinan, who arrived at the court in late 1998, says Kirby "was a congenial person with whom to work" and that he enjoyed going to lunches hosted by Kirby.

All refer to his prodigious work ethic.

"He's relentless," says McHugh. "Every Saturday and Sunday he is in chambers. Seven days a week he works."

"It's a life that's been devoted to work and even his greatest critics would say it's been a life devoted to public service."