Dr Kerryn Phelps made history in October when she became the first Independent – indeed the first candidate not from the Liberal Party or its precursors – to win the blue-ribbon Sydney seat of Wentworth, vacated by former Prime Minister Malcolm Turnbull.

Such was her excitement, and exhaustion after a hard-fought and high-profile by-election campaign, Dr Phelps began her victory speech that night by thanking the voters of Warringah, a not dissimilar peninsular-based electorate on the northern side of Sydney Harbour. Wentworth is wealthier and more cosmopolitan, but Warringah, too, is in the media spotlight ahead of this month’s Federal Election because of a high-profile, celebrity Independent looking to topple another former Prime Minister in the form of Tony Abbott, who’s held the seat for more than 20 years.

Like Dr Phelps, Zali Steggall has put climate change – and other big-vision issues – at the heart of her fight. But the differences between what the two women face on May 18 are also stark: coming from nowhere to take on one of Australia’s best-known and most combative politicians, Steggall has nothing to lose; Dr Phelps, by contrast, will not want to go down as “Member for Just Seven Months”. Rusted-on Liberal voters who lodged a protest against the overthrow of Turnbull in October by putting party candidate Dave Sharma second – or even further down – on the ballot paper may have now forgiven the party, making Dr Phelp’s razor-thin margin hard to defend.

But if anyone can do it, the openly gay media doctor and health and human rights campaigner is the one.

“During my early years, my parents instilled in me the values of diligence, perseverance, integrity, hard work and financial prudence,” Dr Phelps recounted in her first speech to Parliament in November.

“Participation, the pursuit of excellence, a love of the outdoors, involvement in sport and lifelong learning also underpinned my childhood. I grew up in a culture of community engagement—of volunteering—and both of my parents were awarded an Order of Australia for contributions to their community.

“Education was a strong theme in my childhood, fuelled by my own parents’ lack of opportunity for advanced education.

“Through high school, once I was old enough to work, I always held two or three jobs. That became my normal. I was the first in my family to go to university. In fact, I was the first in my family to finish high school. I decided on a career in medicine at a time when the Commonwealth funded university tuition fees.”

As the first female president of the Australian Medical Association – in the mid-1990s – and a media health advocate for decades, Dr Phelps has long been an identity around the leafy streets, Bohemian enclaves and harbour- and beachside suburbs of Wentworth, and has proven extremely effective in the short time since coming to power.

Among her most notable achievements was helping to push through Parliament amendments to Home Affairs legislation effectively taking medical and health decisions about offshore asylum-seeker detainees out of the hands of politicians and public servants and into the care of an independent medical process.

She is also a driving force behind Australia’s transition to a more sustainable economic model, with a 100 per cent renewable energy target among her goals. She, like others, says the current debate about the costs of tackling climate change miss the point.

“We don’t have an exact number of what it’s going to cost,” she says, “but financially it is a smarter decision.

“The cost of renewable technology is getting cheaper and cheaper each day, whilst the cost of fossil fuel technology is significantly getting more and more expensive. So, it is much smarter for the environment and much smarter from an economic point of view.”

Dr Phelps has also called for a ban on all single-use plastic bags; she opposes the controversial Adani coal mine in Queensland, and also wants to do more to help asylum-seekers.

A former Sydney City Councillor and Deputy Mayor, she is also a tireless advocate for services in the electorate, campaigning for a new high school for the eastern suburbs, as well as more money for age care facilities and rehabilitation clinics.

With time ticking down until Australia decides, Dr Phelps and her purple army have become common sights around Sydney’s iconic eastern suburbs.

Will the Liberal-loving voters return to their old ways, or have they embraced the charismatic Independent who shook up the establishment? Like Warringah, Wentworth will be among one of the most-watched electorates in Greater Sydney – and perhaps the country – on Election Night.