Research based on new Census data has shown that life expectancy goes down dramatically as you travel west in Sydney. At its most extreme the gap between average life expectancy in an Eastern Suburb of your choice and Mount Druitt in Sydney’s west is 20 years.

This is shocking.

Having worked in East London for over a decade before I came to Australia I was familiar with the reality of a divided city. Those of us working to transform East London had discovered that for every Tube station going eastwards from the centre of London, life expectancy dropped by a year. That was bad enough but the gap in London at its worst never reached 20 years. Yes, that’s right, in a very key indicator of inequality Sydney might just have a worse record than London.

Though there are complex reasons behind this, a full understanding needs to start with some simple honesty. Self celebration of Australia as the land of the “fair go” has blinded us to the reality of disadvantage amidst plenty. It has put us to sleep when real energy, urgency and focus are required to tackle this problem.

In reality, Sydney is a city divided by wealth and health.

Apart from stubborn islands of poverty and ill health in the inner city and clusters of well-off graduates in and around Westmead and parts of the north-west, there is a clear delineation between a healthier, wealthier Eastern Sydney and the poorer relation in West and Southwest Sydney.

There are two Sydneys. The one to the east of Parramatta has most of the new higher paid jobs, most of the public transport network, fewest new migrants and refugees, and most of the city’s private schools. It enjoys the economic and social benefits of higher density, which means that jobs and services are easily walkable or accessed by mass transit, now understood to be key attributes of cities that succeed for all their citizens.

Western Sydney by contrast currently creates 14,000 people of working age each year but jobs for only 8000 and many of them are low paid. It is taking two-thirds of all Sydney’s homes over the next 20 years, though on current trends these will be in lower density developments, poorly connected to public transport, which inhibits walking or cycling.

These are thus neither job-rich nor healthy environments and are likely to sustain or even exacerbate the divisions within our city. While the new Western Sydney Airport will help to provide new opportunities for high-paid knowledge jobs in the region, and while the excellent Western Sydney University is proving to be a brilliant nurturer of talent for the future, we can and must do better to fill the jobs gap.

This is the backdrop to the differential life expectancy outcomes in Sydney. Poverty, social exclusion and ill health are increasingly concentrating not in denser inner-city neighbourhoods but in the low-density suburbia of Western Sydney, poorly served by public transport, where long car journeys to work – and even to shop – are the norm. There is accordingly serious residential sorting going on in Sydney with fewer and fewer mixed communities of the kind many of us grew up in, to our benefit, forming or being retained.

These dispersed, unwalkable communities have also become breeding grounds for diabetes 2, the deadly urban plague of our times. If nothing is done we shall see more and more evidence that where you live in Sydney determines your life chances.

When we saw how unequal an otherwise booming London was becoming, the councils I worked with in East London started a bipartisan campaign to achieve what we called “convergence”. Our objective was to ensure that within 25 years time, in key economic, educational, social and health outcomes – GDP per head, skills development and school performance, domestic violence and, yes, life expectancy – East London would achieve convergence with the average scores for London overall.

Our ironic but still galvanising slogan was: “fight for the right to be average”. Little did I know when I arrived here six years ago how relevant, sadly, that fight would be in today’s Sydney.

Tim Williams is chief executive of the Committee for Sydney.