Sir William McMahon, Lady Sonia McMahon’s former mansion proposed for demolition

A bold plan to demolish the former home of PM “Billy” McMahon and wife Lady Sonia McMahon to erect a so-called “giant mausoleum” is facing fierce backlash, as Sydney socialites remember the iconic soirees they hosted.

The demolition of the historic former residence of a former Prime Minister to make way for a $5m ultra-modern property is facing fierce opposition from residents, with one describing the planned development as looking like a “giant mausoleum.”

The home, at 18 Drumalbyn Road Bellevue Hill, was owned by Sir William McMahon and his wife Lady Sonia McMahon, and a key fixture in Sydney’s social scene.

Eileen ‘Red’ Bond was close friends with Lady McMahon, and attended many a party, after-party at the house.

“Sonia was a great friend and it was a great house. How many times did we go back there for yet another drink, for another bubbles after we hadn’t had enough?” Ms Bond said.

Australian designer Camilla Freeman-Topper and husband David Topper lodged plans with Woollahra Council in September to redevelop the estate they purchased for $15.75m in 2019. A document by Fearon Hay Architects outlines their vision to replace the 1920s-era house.

The 40-year residence of the late Prime Minister Sir William McMahon is proposed for demolition.

An artist’s impression of the planned build which would replace the historic mansion. Picture: Fearon Hay Architects

The planned five-bedroom development would retain the pool and tennis court but replace the existing home with a boxlike modernist structure comprising a ‘glam room’, home office, and a ‘green roof’ where plants will be grown across the entirety of the roof.

For Ms Bond, the demolition would be a loss of history.

“Sonia was history, so was the house. We mixed socially a lot. Everything is sad when it goes but we can’t keep everything I guess,” she said.

Woollahra lawyer Nick Eddy went to a lot of parties at the McMahon house.

“Sonia would never have demolished that home, she loved it, it was a beautiful big home,” he said.

“She would often have parties and drinks, barbecues and a lot of cocktail parties. Sonia also went out a lot.”

He said a lot of Sydney personalities were regulars at the McMahon parties including the rich listers and founders of Nutrimetics Bill and Imelda Roche, Eileen Bond the ex-wife of Western Australian businessman Alan Bond and Lady Susan Renouf.

Lady Sonia McMahon with former prime minister William McMahon

US president Richard Nixon escorts Sonia McMahon, wearing a famous split dress as husband, as Australian Prime Minister William McMahon follows, to function at White House. November 1971.

Lady McMahon was the matron of honour at Sydney socialite Glen-Marie Frost’s wedding.

“Sonia and Billy were wonderful hosts. A lot of charity events were held there, including dinner parties, parties for birthdays, and anniversaries,” Ms Frost said.

“That’s what I found so interesting at their parties, I got to meet such a diverse group of people in Sydney. A lot of knights and ladies, sirs and ladies, people like Sir John Pagan and Lady Pagan, Sir James Killen, it was very glamorous.”

Lady Sonia McMahon sits on a chair in the courtyard of her home in Sydney, November 1, 1985. Picture: Peter O'Halloran.

Already 24 residents have submitted letters objecting to the development since it was exhibited in mid-October, including Residents First councillor Lucinda Regan.

Ms Regan said the heritage assessment submitted by the owners had failed to fully consider its historic and cultural significance.

“We should at least have a proper look at the heritage… have a second opinion on it before you just say, well, it’s not worth saving,” Ms Regan said.

“Once it’s done, it’s gone.”

Lady Sonia McMahon with Sir William McMahon, 1966.

A Bellevue Hill resident who declined to be named described the new home planned as “something akin to a giant mausoleum.”

The potential loss of the original building suggested the council was “not prioritising important historical homes as they should be,” he said.

“It’s not like a childhood home or anything like that, he lived it in while he was Prime Minister.”

A spokesman for Woollahra Council said it could not comment while the DA was being assessed, but confirmed the outcome would not be determined by council but the Woollahra Local Planning Panel.

Liberal Woollahra councillor Sean Carmichael said the home should be preserved to reflect “Billy” and Lady Sonia McMahon’s legacy as “significant political and philanthropic figures in the life of the eastern suburbs and indeed Australia.”

“I simply hope the planning panel reflects on this history before making a decision, and doesn’t totally destroy it,’’ Mr Carmichael said.