Peter Costello clean bowled before his belated declaration

Nine Entertainment chair Peter Costello, left, announces Mike Sneesby as the media company’s new CEO in 2021. Picture: Britta Campion

In the end, the only real surprise is that it took 75 hours for the final dismissal.

From the moment Peter Costello forcefully shoved journalist Liam Mendes to the floor at Canberra Airport at 1.30pm on Thursday – having taken a clear dislike to the reporter’s straightforward questions – the Nine chairman’s eight-year tenure atop the media giant was over.

The ensuing three-and-a-bit days unfolded like a one-sided Test match. The result was never really in doubt but the various participants still had to complete the game, even if the star player on the losing side was proving immensely difficult to remove from the crease.

A few hours after Costello’s encounter with the young journalist from The Australian at the airport on Thursday, he attended the relaunch of Nine’s revamped new bureau at Parliament House.

Those present say he swatted away the elephant in the room, sizeable as it was, dismissing questions about the airport fracas as “rubbish”. Costello even claimed he never “struck” Mendes, insisting he had tripped over an advertising hoarding.

His use of the word “struck” was telling.

It was clear that the one-time prime minister-in-waiting hadn’t “struck” Mendes, so for Costello to deny he had done so was a clumsy attempt at word gymnastics that fell flat on its face.

Video footage of Costello’s confrontation with Mendes was already leading every major news website on Thursday evening, and topped most 6pm news bulletins. Friday morning’s news breakfast programs were more of the same.

The video, which is still online on The Australian’s website, shows Costello barging into Mendes with significant force. One of two witnesses to the incident described Costello charging “through (Mendes) like a sumo wrestler”.

Mendes was thankfully unhurt. Costello’s reputation wasn’t.

Astonishingly, the former federal treasurer of Australia stood over a young man, whom he had just knocked to the hard airport floor, and walked away without helping him up.

One witness said Costello was laughing as he shuffled on through the airport.

As far as reputational branding went, it was one of the most memorable corporate own goals in living memory.

The next day, Nine News reported that Costello had “gone bush”.

But it’s understood he was sufficiently in range to dial in to a hastily convened meeting of the Nine board on Friday night, during which the Canberra Airport incident was high on the agenda.

That meeting ended – surprisingly – with Costello remaining as chair.

Insiders told The Australian, though, that his position had been identified among company’s senior management as “untenable”, and it was likely that Costello’s reign would end within days.

On Saturday, sources told The Australian that Costello had lost the support of both the editorial floor and management.

To make matters worse, Costello woke on Sunday morning to be greeted by a story in News Corp papers that quoted former Nine chief executive Jeff Browne calling for a “cultural reset” at the company, and a thorough investigation into the incident at Canberra Airport.

By Sunday afternoon, the Nine bunker had gone deathly quiet.

The Australian sent a text message to Catherine West, the deputy chair and Costello’s closest ally on the board, asking whether she still supported the chair. Silence was the only reply.

Similarly, The Australian sent an email to all 11 members of Nine’s management team, including chief executive Mike Sneesby, on Sunday afternoon to ask if any of them wished to come out in support of Costello.

Again, silence.

Just before 5pm on Sunday, Nine notified the Australian Stock Exchange that Costello had resigned, effective immediately, and West was his replacement.

One anonymous source who has worked closely with Costello over many years told The Australian on Sunday night: “He’d be like a wounded bear. But after James Packer had a go at him, and Jeff Browne had a go at him, and others had a public shot at him, he probably just decided ‘enough’.”

For many at Nine, the end of his innings couldn’t have come soon enough.