Every time there’s an election, which is often, some bright spark on the left comes up with an amazing idea. “There are the Tories, right, and Labour, who are trying to stop them, and then there are all these other parties like the SNP and the Lib Dems and Caroline Lucas and the Welsh one. So here’s a thought: what if they all clubbed together and just decided to beat the Tories?”

It’s a compelling thought, if you ignore political reality and you can genuinely imagine Nicola Sturgeon playing Nick Clegg to a Prime Minister Corbyn. If you could get the so-called ‘progressive coalition’ of Labour, the Lib Dems, the SNP and the Greens to vote in perfect harmony, with all their existing supporters voting tactically in perfect harmony to keep the Tories out in each seat, what would actually happen?

Let’s start with the 2015 election results. The Tories needed 323 seats to win a majority, and captured 330. To achieve this they won 11.3 million votes to Labour’s 9.3 million; but if you combined Labour’s vote with the Lib Dem, Green and SNP votes, a coalition could have beaten the Tories by over 3 million votes. That would surely have kicked Cameron out of power, right?

Let’s look at the data, courtesy of Electoral Calculus. (Sensitive Guardian readers and committed socialists may want to look away now.)

I looked at what would happen if every single Green voter switched to Labour last year, and the answer was ‘not a lot’. The Tories would have lost 10 seats and Cameron would still likely have formed a government.

You might think the Liberal Democrats would make a bigger impact. If every single Lib Dem and Labour voter had coordinated perfectly to inflict the maximum possible damage on Tory prospects, it would still have only swung 32 seats – 17 to Labour and 15 to the Lib Dems. Places like Lewes, Eastbourne, Colchester, and Portsmouth South would have swung to the Lib Dems, while constituencies like Thurrock, Watford, Telford and Warrington South would have been nudged into Labour’s column.

Facebook Twitter Pinterest A perfectly-executed Lib/Lab pact could have only captured a handful of seats from the Tories in 2015.

That would have left the Tories on 299, but with the Lib Dems now on 23 and Labour still far behind on 249, the likelihood is that the existing Coalition government of 2010-15 would have continued.



To have any chance of toppling it the Green, Lib Dem and Labour votes would have had to be perfectly coordinated. SNP voters would make little difference, as the Tories only have 1 seat in Scotland anyway. This would have reduced the Tories to 286, and an alliance could technically have made it over the line with about 340 seats. But with Labour still trailing the Tories on 259 seats, a constitutional crisis would have been more likely than Ed Miliband entering Number 10.

These are of course ridiculous scenarios. Even if it were true that 100% of Lib Dem, Green and SNP voters preferred a Labour government to a Tory one, which is complete nonsense to start with, getting every single one to vote correctly - or at all - would be impossible. A progressive coalition may have been mathematically possible - just - in 2015, but in reality it was totally implausible.

Much has changed since 2015 of course. We’ve had the EU Referendum, a shiny new Prime Minister, and 18 months of Jeremy Corbyn scowling on the telly, so are things looking up for the progressive coalition idea?

HA HA HA HA HA HA HA HA HA HA HA HA HA HA HA HA HA HA HA HA HA HA HA HA HA HA HA HA HA HA HA HA HA HA HA HA HA HA HA HA HA HA HA HA HA HA HA HA HA HA HA HA HA HA HA HA HA HA HA HA HA HA HA HA HA HA HA HA HA HA HA HA HA HA HA HA HA HA HA HA HA HA HA HA HA HA HA HA HA HA HA HA HA HA HA no not really.

Let’s look at some updated figures: and please don’t hate me, I’m just doing maths. Electoral Calculus keeps an updated projection of vote tallies on its site, based on recently polling. Yes polls aren’t perfect, but neither are they particularly inaccurate. The numbers won’t be spot on, but they probably won’t be miles out – the basic character is the same either way.

Facebook Twitter Pinterest Perfect tactical voting by Lib/Lab/Green voters, even assuming they preferred a Labour government to a Tory one, would fail miserably based on current polling.

At present, the Tories look set to win about 392 seats with Labour crashing to the Hagueish total of 170. A perfectly-executed Lab/Lib pact could reduce that to about 361, handing 25 seats to Labour and 6 to the Lib Dems. SNP voters can make little difference since progressives already hold 58/59 Scottish seats and the Tories aren’t expected to gain any. If all progressive voters were directed by an all-seeing omnipotent god-being to perfectly optimize their vote then the Tories would land in the 330s. That would still leave them over 100 ahead of Labour (on 217) and be enough to form a majority.

In summary: even if a progressive coalition made any sort of political sense in a reality where Tim Farron and Nicola Sturgeon would have to prop up a guy who can’t even claim a majority of his own MPs; it would require a polling error unlike anything we’ve ever seen combined with literally an act of God for it to work.

Good luck with that, guys.

