However, Cannon-Brookes eventually re-emerged and amassed an 11.3 per cent interest in AGL. The Atlassian co-founder then launched a successful campaign to convince other shareholders to block the board’s proposed demerger, arguing that splitting AGL into smaller entities would leave it less able to fund the investments needed to bring forward the closures of its coal-fired power stations that are not currently due to retire until 2045.

He also insisted AGL would have a better future if it remained a single company that could use its giant retail base of 4.5 million customers to harness clean-energy technology.

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The board last month bowed to intensifying shareholder pressure and abandoned its plans to demerge its power generation businesses following months of pressure from Cannon-Brookes. It also announced the resignations of chief executive Graeme Hunt and chairman Peter Botten as well as independent directors Diane Smith-Gander and Jacqueline Hey, with remaining board directors set to conduct a strategic review into the future of the 180-year-old company.

AGL shares rose slightly following news that Brookfield had become a minority shareholder, but ended the day 1.7 per cent lower at $8.25.

Jamie Hannah, deputy head of investments at VanEck Australia, one of AGL’s top shareholders, said he would not support any new takeover play while the company was undergoing its strategic review and trading at its current stock price.

“It would be highly detrimental if Brookfield decided to do something now,” Hannah said. “I was not on board with their previous takeover offer, and I’m still not on board now ... I think there is still long-term value within the company.”

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