John Della Bosca didn’t attend The Sydney Institute’s 20th Anniversary dinner last night but he was there in spirit, with most of the 730-strong guests relishing the details of d’affaire della Bonquer.

Most cheerful person on the night was News Ltd’s group editorial director Campbell Reid, who was basking in the limelight of a genuine scoop, delivered to the readers of the Tele that morning. Conspiracy theories abounded — was some party rival behind this? — but this morning’s story says it is the classic tale of a woman scorned. Kate, 26, was tired of waiting for Della to leave his lovely wife, Belinda, and went postal.

Herein lies the problem with May-December romances; in the good old days, younger women, especially those closely acquainted with the leatherette of the parliamentary couch, kept their mouths shut. But Generation Y has no notion of privacy or propriety or being embarrassed about bonking a married man. She freely discussed it with her friends, and probably posted it on Facebook. And she kept all the text messages. The most troubling part of it is that she thought he was “hot” and “sexy”; just how did she get that Labrador past security??

But back to the night. I love The Sydney Institute dinners; they are one of the few opportunities to spot some serious jewels, slung around the necks of some serious players. And in honour of the guest speaker, Her Excellency Quentin Bryce AC, one of the country’s best-dressed women, everyone had scrubbed up.

Nick Greiner introduced the G-G, giving a short history of the Institute, with a run-down of some of its high-profile speakers and recent talks. Earlier this year members had gone to a discussion entitled “The Politics of Desire”, which was very relevant “given the events of today,” he quipped.

Her Excellency started by thanking hosts Gerard and Anne Henderson, describing the Institute as an “important gatherer of people and ideas; an agent for discussion about the things we care about; a forum for thinking aloud; and a chance to catch up with friends and colleagues at the end of long working days.”

“There’s no doubt that part of its enduring success and following is due to the fact that one declines an invitation from Gerard Henderson only at one’s peril. Always better to turn up I think, hear what he has to say about you, and hopefully stare him off the worst of it!”

In purple silk with a diamond clasp, she spoke moving about her childhood in rural Queensland, saying that the friendships in her small community were “based on what you gave, not on what you earned.”

On the day of her inauguration, she said, her elder sister Diane had told her, “you remember who you are. In the past two months that is what has stayed with me.”

It was a glittering audience, including current pollies Maxine McKew, who was sitting between Ashok Jacob and Allan Moss, a happy-looking Barry O’Farrell with Greg Smith and Pru Goward, and David Campbell, who was keeping a low profile. Although Malcolm Turnbull’s new media adviser Mark Westfield was there, the boss was absent.

The sisterhood was out in force, including Anne Summers, whose new book is a runaway bestseller, Wendy McCarthy, Ann Sherry and Helen Lynch, who has just walked the Camino and is preparing for an 11-day walk between Kyoto and Tokyo. Gail Kelly looked fantastic in a satin frock, proving that not all bankers are boring, but Heather Ridout had the stand-out rocks, a mighty string of lustrous South Sea pearls.

Rodney and Lyndi Adler sat on the table of Albert and Sophie Wong, reminding me of the days when the annual dinner was called the Larry Adler memorial lecture. Nearby was Mark Scott, Maurice Newman, Kim Williams and most of the staff of the Lowy Institute. All up, a rubber-neckers delight.

Bob Carr gave the vote of thanks to Quentin, saying he had been at another function beforehand where he was the only man in a dinner suit. He was dressed that way, he had explained to his fellow guests, because things were so tough in banking that he now worked three nights a week pulling beers at the Texas Tavern. This had been accepted without question, he said.

By positioning myself beside the door, I was able to crash-tackle Barry O’Farrell on his way out.

When I asked him what he thought about the Della affair, there was a long pause. “What it means”, he said, “is that I am going home early to be with my wife.”