Illustration: Joe Benke And will Albert Park join Prahran south of the river in going Green? "It's a mixed bag," one senior Labor strategist told The Sunday Age. "You've got your stereotypical affluent, tertiary-educated professionals. They're the Greens' praetorian guard, the people who give them ballast, keep them growing. "Then moving down the economic scale a bit, you'll find teachers, nurses and public servants voting Green. We find that group can be split down the middle with half voting Green, the other half voting Labor."

High Street in Thornbury, part of the electorate of Northcote. Credit:Ken Irwin While the Green tide has been lapping at the terraces and cafes of the inner city for the past few years, the sheer force of the wave that recently crushed Labor in Northcote surprised many observers. One reason for the gnashing of teeth is that Northcote was once a jewel in the Labor crown, the seat of party royalty like John Cain Snr. When Steve Bracks came to power in 1999, the ALP had a primary vote in the seat of more than 66 per cent. On two-party preferred, it sat third on the ledger as the party's safest. The Greens MP for Northcote, Lidia Thorpe. Credit:Paul Jeffers In nearby Brunswick and Richmond, seats that look likely to turn Green at the next state election, the picture was similar.

The Greens were invisible before the turn of the century, winning just over one per cent of the vote statewide. Ellen Sandell celebrates with supporters after winning Melbourne in 2014. Credit:Wayne Hawkins "It was part of your self identity, it was tribalism in those suburbs to vote Labor," said Monash University politics lecturer Paul Strangio​, who wrote Neither Power Nor Glory: 100 Years of Political Labor in Victoria. "Those seats were working class, Catholic, industrial areas. "If anything else what we see in these electorates is just a window into that dramatic socio-demographic transformation of the inner city that's gone on for decades now."

By now, everyone is fully aware of the rapid gentrification sweeping once poor tough suburbs. Brick factories making way for concrete apartment blocks, as the middle class moves in and the working class shifts further out. Far and away, the biggest change 10km from the CBD has been the influx of wealthy professionals. In 2001, weekly household income in Northcote was lower than the state average. Now, the area earns $300 a week more on average than Victorian households. Professionals once made up less than 20 per cent of jobs in the seat, 15 years later it is closer to 40 per cent. The changing class make-up of Brunswick and Richmond has been just as substantial. All three boasted strong migrant populations, particularly Northcote and Brunswick, where Greeks and Italians represented significant chunks of the community. Those numbers have diminished as the average mortgage has skyrocketed. And fifteen years ago, before the rush to live closer to the city, people who owned their homes outright outnumbered renters and mortgagees in Northcote and Brunswick. Not any more. Rent, meanwhile, has risen by at least 140 per cent in all three seats.

Aaron Martin, senior lecturer in political science at the University of Melbourne, said the new inner-city voters were post-materialists; comfortable in their economic situation, they become more concerned about social issues such as refugees, race and the environment. In Northcote, as Labor campaigned hard on a platform of housing affordability, posters for Lidia Thorpe emphasised that she would be the first Indigenous woman in state parliament. Local Greens policies addressing development and schools sat alongside the creation of a Great Forest National Park. "When people voted along class lines, it was much easier for parties. It was 'are on the side of capital or are you on the side of labour?'. It was more complicated than that but it was the basic dichotomy," he said. "In the past few decades, that's been fractured." While Northcote, Brunswick and Richmond have shared similar trajectories, other seats that have already turned Green have taken a different path. In Melbourne, which elected Ellen Sandell in 2014, household income is lower than the state average. Brunswick resident Eric Butler, 26, said he's happy with the rise of the Greens, but was not sure why it's happening.

"There are definitely more apartments and people are definitely getting whiter and richer," he said. Brighde Sullivan, also from Brunswick and also aged 26, said the Greens' values were aligned to her own, particularly on refugees, the environment and same-sex marriage. "They've supported those (issues) all the way through which has been important," she said. Eric Butler lives in Brunswick and is happy with the increasing Greens vote. Credit:Joe Armao Meanwhile, in the seat of Melbourne, the ethnic make-up has increased, with 19 per cent speaking Mandarin at home, according to the 2016 census. Crucially, however, the seat is flush with university students, who make up more than a quarter of people who live there. The average age of the seat is 27 - 10 years younger than the Victorian average.

The other seat belonging to the Greens in parliament is Prahran. The seat is wealthy, has a high proportion of renters, nearly 60 per cent of properties, and almost the same amount of couples without children. That seat appears likely to continue as a three-cornered contest between all three parties. Nearby Albert Park, older and wealthier than the rest, might be the hardest of the lot to crack. The Greens keep "detailed analysis" on the demographics of their voter base but are not keen to make them public. Other factors believed to manifest in a Greens vote included high levels of education, being in a defacto couple and not following a religion. Older baby boomers who came of age voting for socially progressive Labor leaders like Whitlam are prime targets for the Greens, as are the tens of thousands of millennials that signed up to take part in the same-sex marriage survey. The next decision facing Labor is whether to abandon their once impenetrable heartland and focus on other seats further from the city. "These seats are deeply important to the Labor psyche," said Mr Strangio. "Just to shrug their shoulders and concede them is awfully difficult."