By-elections have been a feature of Australian political life since the first democratically elected colonial parliaments were established in the mid-nineteenth century.

Compiling a comprehensive set of historic by-election results at state as well as federal level would involve painstaking research through the archives of various electoral authorities and newspapers-of-record.

It is possible that, buried in some such dark and dusty place, there might be found details of a by-election defeat as bad for a major political party as the one suffered by New South Wales Labor in Penrith on Saturday.

However, the lack of any such precedent in recent memory, together with the trend towards greater electoral volatility over time, suggests it isn’t very likely.

We do know that Labor has suffered the worst by-election swing recorded in the long history of New South Wales, thanks to exhaustive historical results compiled for the New South Wales Parliamentary Library by Antony Green.

The closest historical parallels that spring to mind are indeed from the Premier State: Bass Hill in 1986, when Neville Wran’s previously safe seat fell to the Liberals upon his retirement, and — distressingly close at hand as far as the government is concerned — Ryde and Cabramatta just after Morris Iemma’s departure in September 2008.

With respective two-party swings of 22.2%, 22.9% and 22%, Penrith looks to have surpassed all three, recording an election night swing of 25.5%.

One result that has its measure is the 1991 by-election for Geraldton in Western Australia, held as Carmen Lawrence’s Labor government groaned under the weight of revelations from the WA Inc Royal Commission.

On that occasion Labor’s primary vote fell from 47.6% to 16.6%, while the combined Liberal and Nationals vote went from 43.5% to 66.5%. Labor finished third behind the Nationals and thus did not even make the final two-party cut, making it impossible to determine a two-party swing.

It might also be worth mentioning Labor’s forfeit last year in the Tasmanian upper house seat of Pembroke, which the party was too scared to contest after the resignation of its sitting member Allison Ritchie.

(It should be stressed that this is limited to two-party contests, and thus excludes the fairly common occurrence of major party support being gouged by the emergence of popular independents. And while I’m making asides, it’s interesting to note that the by-election hall of shame is dominated by Labor).

In Penrith, Labor finished the night on 24.4% of the primary vote, losing almost exactly half of their 48.7% from 2007.

Three-quarters of the dividend was collected by the Liberals, up from 32.6% to 50.9%, while the Greens vote more than doubled from 5.5% to a still quite modest (for a by-election) 12.8%.

While the result has never been in doubt since former member Karyn Paluzzano announced her resignation in May, Labor might initially have hoped for something a little less bruising.

At the time of the 2008 by-elections then Premier Nathan Rees had a Newspoll approval rating of 39%, which — mediocre as it was — proved to be a honeymoon peak. It clearly says something very alarming about the state of the Labor brand that Kristina Keneally has been able to do even worse with an approval rating of 47%.

Several factors suggest themselves as explanations for Labor’s ability to plumb new depths, of which the most newsworthy is the decline in Labor’s federal fortunes since Ryde and Cabramatta. Evidence of Rudd government policy failures feeding into a general questioning of Labor’s competence in the electorate might be anecdotal, but it’s substantial in volume.

Of course, those rushing to judgement on the Prime Minister need to recall that the by-election follows a horror stretch for the state government, even by its own abysmal standards.

There is also reason to think Penrith was especially unfavourable terrain for Labor to face a by-election.

As the experience of the corresponding federal electoral of Lindsay has shown, this is an area of fickle political loyalties that never fails to jump on the bandwagon when a swing is on.

The electorate’s outer suburban location also places a premium on transport issues, with local voters having suffered the worst of freeway gridlocks and a creaking public transport system.

A somewhat more nuanced picture of the result can be gained by comparing the two distinct parts of the electorate: Penrith and its surrounds, which account for about 80% of the voters, and the very different electoral terrain of the Blue Mountains, which the electorate touches upon at Blaxland, Glenbrook and Lapstone.

Labor was hit hardest in the former, down by about 26% compared with 21% in the Blue Mountains, and the dividend there more heavily favoured the Liberals.

There have been suggestions the Greens could have hoped for more from a Labor collapse on this scale, but the distinction between the two areas suggests their failure to do so says as much about Penrith as the state of the parties that large.

Penrith boasts slightly above average incomes but below average educational attainment, making it weak territory for the Greens. By contrast, the Blue Mountains has almost double Penrith’s proportion of professionals, and is thus a lot more representative of the kinds of seats where the party will be hoping to defeat Labor.

It is thus highly significant that the Greens out-polled Labor in every one of the four Blue Mountains booths, polling a collective primary vote of over 23% compared with about 11% in and around Penrith.

Accordingly, the result holds little comfort for Labor in the Greens targets of Balmain and Marrickille, and suggests they will struggle to stay ahead of the Greens in the neighbouring seat of Blue Mountains — academic though that may be, given the near certainty of it falling to the Liberals.

And while federal implications of state by-elections should generally be treated with caution, the scale of the overall result gives Labor ample reason to be nervous not only Lindsay, but also the other nearby marginals of Macquarie and Macarthur.