Via John Band, I found this very interesting chart on Australia’s ABC network’s coverage of the election:
First, take your moment to be jealous of those in Australia who can have a good night’s sleep before watching the results, then take a look at the figures and see if the same question comes to you as me: why have election counts slowed down so much over the last twenty years?

In 1992, we had the majority of results by 2am, from 1997-2005 it took until 3am, then last time it took until past 4am to get past 50% of the results. There looks like a general downward trend over time, though turnout obviously has an effect – 2001 seems marginally quicker than 1997, as turnout fell from 1997 to 2001 – but 1992 was noticeably quicker than the subsequent ones, and 2010 involved a lot of waiting for results.

There’s a few possible explanations I can think of:

Impact of local elections: 1992 was the last time we had a general election that wasn’t concurrent with the local elections of that year, so the process of verification of the votes didn’t need to involve sorting and checking the local elections too. 2010 also broke the cycle of the previous years of being at the same time as mostly County Council elections, happening instead at the same time as London boroughs and other boroughs and districts across the country.

Postal voting: The change to postal voting on demand happened after 1997, meaning returning officers now had to devote more time to opening and checking postal votes, though much of the grunt work in this could be done before the day itself, so I’m not sure how much of an effect it had.

Fewer people counting: I don’t have any evidence one way or the other on whether budgets for counts have gone up or down over the year, but obviously if fewer people are being employed to do a count, it would take longer.

More candidates: As anyone who’s been part of a count will tell you, it takes longer when there are more candidates, as sorting the votes into an increasing number of piles takes more time, then each one has to be checked separately and larger ballot papers take longer to unfold.

There are probably other explanations but those are the ones that spring to mind first for me. Now, if someone wants to give me a large sum of money, I’ll gladly undertake a research programme to find out exactly what the cause was, and how we can make them faster in future.