Diana Killen, aged in her early 20s, was working in a new educational section of the National Library by the shore of Canberra’s Lake Burley Griffin when word hurtled through the building that Gough Whitlam and his government had been sacked.

She and colleagues abandoned their desks and hurried 700 metres up the road to the lawn opposite the old white wedding cake of a building that was Australia’s parliament house.

There, they were absorbed within a roiling throng of disbelief, excitement and outrage as offices across the national capital emptied and thousands of their inhabitants rushed to take part in the greatest show in town.

It was 50 years ago next month: Tuesday, November 11, 1975.

Killen says she has never been “a protesting sort of person” and did not join the chanting and tumult swirling around her.

“I was just standing there incredibly surprised,” she says. She pauses and adds, “yes, that’s an understatement, to put it mildly”.

Shortly before 4.40pm, Whitlam, prime minister for just 35 months, appeared on the steps of Parliament House, navigating his 194-centimetre frame through a storm of journalists, parliamentary officers, MPs and nervous Commonwealth police, there to loom mightily over the shoulder of the governor-general’s official secretary, David Smith, as the crowd chanted, “we want Gough, we want Gough”.

Killen remembers Whitlam’s voice booming over a loudspeaker as Smith finished reading the proclamation dissolving the parliament and thus formalising what would ever after be called The Dismissal, with the words “God Save the Queen”.

“Ladies and gentlemen, well may we say ‘God save the Queen’,” thundered the newly sacked Whitlam, “because nothing will save the governor-general.”

Half a century later, it remains among the most memorable lines in Australian political history.

Whitlam, however, wasn’t finished with his grand denunciation.

Malcolm Fraser, the opposition leader newly installed as caretaker prime minister by then-governor-general Sir John Kerr, would “undoubtedly go down in Australian history from Remembrance Day 1975 as Kerr’s cur”, Whitlam declared.

He urged the crowd to “maintain your rage and enthusiasm”.

Those loaded words rolled across Australia’s radio stations, inflaming passions across the land, and television channels beamed the vision over and over in full colour introduced only months before.

Friendships would be strained and broken, households became verbal battlegrounds and furious protests rocked the streets of big cities as Australians digested the news and took sides.

In a month, voters delivered their judgment.

Most of them, it turned out, rejected Whitlam’s advice to maintain their enthusiasm for what had become in its dying months a scandal-wracked, virtually paralysed government.

Fraser and his Coalition won the December 13 election in a landslide.

Killen, like many young Australians, voted Labor in 1972 (“How could anyone vote for Billy McMahon?” she says) and she still approves of the Whitlam government’s storming program of legislation that transformed Australia.

But she was not quite just another bystander at the Dismissal.

Her father was one of the Liberal Party’s most distinctive figures, Jim Killen, a parliamentarian since 1955.

After the excitement of the day subsided, Diana had dinner with her father, and found him morose.

Wedded to the Westminster system of government, he was troubled that the governor-general had sacked a government, using “reserve powers” that were not codified within the Constitution.

A skilled orator, noted wit and barrister known to charm juries and judges, the elder Killen was also tough as a Mallee bull. He began his working career after running away from school to become a jackaroo in outback Queensland. His father had died when Killen was just two, and he was determined to send money to assist his mother, who ran a boarding house in Brisbane.

During World War II, he joined the RAAF, growing the “air force” moustache that would distinguish him for the remainder of his life.

Killen’s talents as a young MP, however, were overlooked by prime minister Bob Menzies, despite Killen winning his Queensland seat of Moreton in the federal election of 1961, saving Menzies’ government from defeat.

Killen concocted a story that Menzies had congratulated him with the words, “Killen, you are magnificent”, though Menzies had not contacted him at all.

No frontbench spot was forthcoming, but legend has it the irrepressible Killen used his sharp sense of the ridiculous to put things to right years later when he visited Menzies in hospital.

“You know, Killen, there was a time when I seriously doubted your judgment,” Menzies told him.

“What a remarkable coincidence,” Killen shot back.

The Dismissal proved Killen’s path to cabinet. Fraser made him minister for defence, and he remained in that powerful job for the next 6½ years.

Did Whitlam treat him with the haughty contempt he might have offered to a prominent member of the political team led by “Kerr’s cur”?

Not a bit.

Whitlam certainly maintained his rage at John Kerr. He never spoke to him again, reserving his towering disdain for the printed word.

After Kerr made a drunken fool of himself at the 1977 Melbourne Cup, Whitlam personified him in his book, The Truth of the Matter, as a Caligula-like figure, “weaving his way down from the imperial box and making his merry remarks to the owner, the fascinated crowd and a million viewers [who] may have thought that the horse would have made a better proconsul”.

But Whitlam could not bring himself to dump on those he respected on the Coalition benches, including Killen.

There was a mutual esteem going back many years. Whitlam and Killen sent scrawled notes to each other in the parliament, and Whitlam sent postcards to Killen from every country he visited. That correspondence now resides in the National Library.

Diana Killen confirms the friendship became so firm that Whitlam and her father made a pact: one would deliver the eulogy for the other, depending on who died first. And so, Whitlam delivered the memorable eulogy for Sir James Killen at the Gothic St John’s Cathedral, Brisbane, in January 2007.

It may be difficult for many of us who have become accustomed to the pettiness and polarisation that has characterised politics in the 21st century to comprehend that cross-party friendships ran deep among many of the hardest parliamentary players in the second half of last century.

Way back in June 1951, at a grand Jubilee ball in the Parliament House’s King’s Hall, Menzies wept and told everyone to go home when he learned that Labor’s Ben Chifley had died.

The two leaders had fought furious election battles in 1946, 1949 and 1951, but they maintained a private friendship, merrily swapping trashy mystery novels, some of which remain at Chifley’s old home in Bathurst, according to Campbell Rhodes of the Museum of Australian Democracy, which these days inhabits Old Parliament House.

Killen maintained some of the more famous cross-party friendships, particularly with long-term Labor prankster and wag Fred Daly.

“Oh yes, Fred Daly is one of the closest friends I have in the world, and Gough Whitlam,” Killen told an interviewer for an oral history project in 1993. “And no two people, to my recollection, have insulted each other, or tried to, as much as Daly and I have.”

After Labor won government in 1972, Daly felt a lot of the new MPs had never seen a proper verbal brawl. He told Killen they should stage one. Daly said: “I’ll make a speech, and I’ll bore it into you, and you can follow me. You can do or say what you like.”

Killen recalled: “So this happened and the fellow, one of his colleagues, went to Fred and said, ‘By Jove, that Killen’s a mean minded so-and-so, isn’t he?’ Daly said, ‘Oh yes, he’s even worse than that. You should see him when he really gets angry.’

“And this fellow ... the look on his face when he saw the two of us go off to dinner together – he just couldn’t believe it.”

Many Australians couldn’t quite believe it, either, when Whitlam and Fraser eventually softened and became friends.

From the 1980s until Whitlam died in 2014, they met for natters wherever it was convenient, and demonstrated publicly together against the threat of foreign ownership of the Fairfax media empire.

Fraser said he’d never resented being called Kerr’s cur because it was “just politics”.

When the Old Parliament House closed as a constitutional chamber in 1988, John Howard and Bob Hawke linked arms at a late-night party and sang – glory be – the trade union anthem, Solidarity Forever.

Years later, after a National Press Club lunch where the two former leaders sat on stage together reminiscing and clasping hands, I asked them if the story was true.

Yes, these old adversaries chuckled, and argued about who had the better singing voice.

• The 50th anniversary of the Dismissal will be marked by an all-day panel discussion and exhibition at the Museum of Australian Democracy (Old Parliament House) on November 11. Diana Killen will be among numerous speakers, including the current Governor-General, Sam Mostyn, and former prime ministers John Howard and Paul Keating. Free tours of Old Parliament House will be offered. Among those who will discuss personal memories of being in the building during the events of November 11, 1975, will be Niki Savva, political commentator, author and board member of Old Parliament House. Audiences across the country and around the world can watch the events online (see the Museum of Australian Democracy website), while visitors to the museum can view them on multiple live screens throughout Old Parliament House.