If they had an election in Britain right now and only 18-24-year-olds voted, Labour would win 600 seats in the parliament and the Conservative Party wouldn't win any (says a poll reported in the Guardian).
But if only retired people voted, the situation would be almost completely reversed: 575 seats would go to the Conservatives.
The same pattern, but less acute, showed up for other age groups: the older British voters are, the more likely they are to vote Tory.
The changeover age – when the voter drift from Labour to Conservative becomes a stampede – is 47.
The trend is more acute among women, who are more likely than men to vote Labour if they're young and more likely than men to vote Conservative if they're old.
Britain has first-past-the-post voting so the outcome is more extreme than it would be here in New Zealand under MMP, but there's no reason to doubt we share the underlying condition.
And not just in voting. In Auckland, the best evidence for the generational divide is in the ongoing debates about what housing developments should be built where.
Housing and Urban Development Minister Phil Twyford has had a go at "nimbys" recently, accusing them of frightening city councillors and holding back essential development.
Nimbyism is the state of believing in a social good as long as it happens "not in my back yard". It's an excellent example of our capacity to hold two conflicting ideas as the same time.
One is that we want our fellow citizens to take a big picture of development and not think selfishly only of the impact it will have on them. And the other is that we want to protect our homes from shade, blocked views, excess traffic and all the other potentially adverse consequences of squeezing more housing inside the city's existing boundaries.
It's legit to want to protect what's yours, especially if it cost you a lot of money, especially if it is, by far, your most valuable asset. And we tell ourselves it's only fair that the views of people most directly affected by change should be properly acknowledged. There are no self-professed nimbys and everyone becomes one if circumstances dictate.
But wait. Everyone? What about the people who don't own their own homes?
On the whole, they don't get the chance to be a nimby.
We used to tell ourselves that was more or less acceptable, because we used to live in a society where most people could expect, if they worked hard and saved hard, that one day they would be able to join the ranks of homeowners.
This is no longer true. It may become true again, if we build enough new affordable houses, but it is not true now. Home ownership is at a lower level in New Zealand than at any time since 1951.
The rate has been falling for nearly 30 years, since it peaked in 1991 at 73.8 per cent. Now, a mere 62.3 per cent of us own our homes, according to Statistics NZ.
On that trend, it's possible most young people now will never own their home. Economist Shamubeel Eaqub calls them Generation Rent.
Both National and Labour are culpable. Both allowed the tax system and other regulations to favour property over other forms of investment, with profoundly anti-social consequences.
Both allowed the housing market itself to focus on the top end, so that we now have a crippling shortage of decent homes for low-income households and hopeful entry-level homeowners.
It's hard to think of a previous occasion when our economy has been so deliberately structured to produce such a generational divide. And it's not just a generational issue.
As has always been the case, low-income people are far less likely to own property. Māori, in particular, are half as likely as Pākehā to own their home.
Addressing this disparity is what the massive housing build starting up all over Auckland is about, and it's one of the things the new public transport networks are about too.
The programme is enormous, the progress will be slow – you can't plan, consent and build thousands of homes overnight – and each step along the way will be fraught with difficulty.
We've discovered, on Dominion Rd, that the existing Unitary Plan is not fit for purpose.
Dominion Rd is a transport corridor that should be perfect for dense housing development with retail at ground level, but objectors there succeeded in halting a five-storey project intended to provide exactly that. Even the council was confused – to put it mildly – about what to do.
How did that happen? First, because when the Unitary Plan was established, objectors succeeded in preventing Dominion Rd being zoned for easy mid-level development.
And now, objectors have succeeded again in preventing a development that wanted to go a bit higher than the zoning allows.
Meanwhile there's a debate starting up, again, about Auckland's golf courses. The city has 32 and the council owns a dozen of them. Too many? Golf's a very popular sport, and not just among the wealthy.
But as Cr Penny Hulse says, Auckland needs parks for a variety of uses, including more playing fields for other sports, children's play areas, wilderness areas and general use parkland. Plus, of course, more housing, some of which might perhaps go on the fringes of some of those courses.
It seems entirely reasonable to think the needs of golfers can be met if they lose some but not too much of what they have now. But will golfers see it that way?
We need to build a larger consensus on how to approach all this. It's our great city-building project, and it doesn't need to mean one side or the other loses out. Currently, though, one side – the young and the less well off – really is losing out.
So developers need to improve their consultative practices – that's especially true for council-controlled outfits like Panuku, and the council itself, but it also applies to the private sector.
Planners and urban designers need to lift their ability to inspire us all. Government agencies, especially Housing NZ, need to show us they really are building the strong, well-designed, well-appointed new communities that Minister Twyford likes to talk about.
Media too needs to see the big picture. Cast a critical eye over the supposed good that will come from each new project, certainly, but not become obsessed with the gripes of those who will always say no, or who do not care at all about longer-term values or the greater good.
We have council elections coming at us next year, and in Auckland they're first-past-the-post, just like elections in Britain. Any chance they'll bring out the best in us?