What would a really big Labour win look like?

Running through one plausible scenario

I asked the Bing AI to make an image of a Labour landslide. I don’t know where the guitar came from.

At the start of the year, I like to do a thread of predictions on Twitter (and this year on BlueSky too)¹, taking requests over Christmas and then posting my expectations. Most of the questions this time around were about the coming election, and rather than make a bunch of isolated (and possibly contradictory) predictions, I decided to work off my New Year’s hangover producing a lengthy thread thinking through one election scenario systematically: a scenario where Nigel Farage intervenes and boosts ReformUK, Scottish Labour continue their big advance of the past year, tactical voting remains intense, and Labour’s overall polling advantage holds. This isn’t the only plausible election scenario by any means, but it is a perfectly plausible outcome based on the current polling and electoral landscape.

Discussions of the ways in which Labour might under-perform are ten a penny right now. But there’s very little consideration² of the opposite possibility: what would have to happen for Labour to win really big? This thread was my effort to work one Labour landslide scenario through step by step. It is not a high confidence prediction. But it is a real possibility that I think is both plausible and deserves more attention.

Step 1: Nigel sticks his oar in

I start with ReformUK and Nigel Farage - as predictions here have repercussions across the rest of the piece. Will Farage return? If he does, he will certainly play a starring role in the ReformUK election campaign. As this recent excellent Tom McTague piece on Farage and ReformUK has made clear, the unusual structure of ReformUK - a company with Farage as majority shareholder - means Farage can take over, or take any other role he wants, any time he wants. ReformUK is a vehicle by Farage, of Farage, for Farage.

The case for a return is clear - there's once again a market for Farage's personal politics - a mix of opposition to immigration, attention seeking and populist raging at failed elites. Conservative disaffection with a failed government, and media boredom about an uncompetitive election will both play in his favour - Tory voters and journalists alike will love to make Farage the story. Even Brexit, seemingly a weakness, can be a strength for Farage. He could mobilise disaffection among Leave voters by campaigning against the Conservatives as the weak and incompetent betrayers of "true Brexit."

The case against? Farage would have to abandon a burgeoning media career, and would risk being blamed for Tory defeat, which might weaken his influence within the Conservatives. A big Reform UK vote could help drive a large Labour majority, free to pursue policies Farage dislikes (including moving closer to the EU) for a decade or more.

On the other hand, a Labour landslide featuring a large ReformUK vote will make it easier to convince Tory MPs and activists that coming to terms with Nigel, and tacking to the populist right, is the only route to recovery. A Tory party which is thrashed despite a weak ReformUK vote will be more likely to see a return to the centre ground as the only route back to electoral health.

It’s a hard call, and one I have relatively low confidence in (60%) but this scenario hinges on assuming Farage comes back. The lure of the limelight, the chance to make the running, and the opportunity to once again influence the post election Tory debate will prove to be enough, and the main agent of chaos in British politics returns to the fray.

The return of Farage will mean a much higher ReformUK vote at the general election. Without Farage, I expect their current c.10% vote in the polls would get squeezed - Reform have persistently failed to match their polling strength in local and by-elections. Farage’s star power with social conservatives and Leave voters will firm that vote up. A Farage focussed campaign could deliver a 10% total vote in England and Wales, which would be roughly halfway between UKIP's performance in England and Wales in 2015 (14%) and the Brexit party's average performance in the seats where it stood in 2019 (5.5%).

This would mean an 8 point rise in the total vote for ReformUK in 2024 compared to its predecessor the Brexit Party in 2019 in England, and a 5 point rise in Wales. However, in seats which were already Con in 2019, the rise will be bigger, because Brexit Party didn't stand candidates in any of those seats in 2019. This support is likely to draw heavily from 2019 Tory voters, particularly in seats where the Brexit party didn't stand last time. The relationship won’t be 1:1 - ReformUK will draw off some anti-incumbent or anti-system votes that might otherwise have gone to Labour - but the Conservatives’ exposure to ReformUK is much higher now because the 2019 Tory voter coalition is much more ‘UKIPpy’ than earlier Tory electorates.

Step 2: Tactical anti-Tory voting by Greens and Lib Dems

Next the LibDems - I suspect their aggregate vote won't change much, but will instead shift around geographically and politically. So a 12% total GB vote for the Lib Dems, similar to 2019, but much more efficiently distributed.

The Liberal Democrats will go up a lot in seats where they're second and competitive, but tread water in very safe Tory or Labour seats, and go down a lot in Conservative or SNP seats where Labour are second. The greater efficiency will reflect the changed basis of Lib Dem support - in 2019 they were primarily a Remain party, now they are running as an anti-Tory party. The loss of some strong Remain voters from 2019 will be balanced by the gain of strongly anti-Tory voters who were put off last time by Corbyn, and the trade-off will be electorally efficient. Anti-Tory voters will coalesce behind the Lib Dems where they can win, while last time the Lib Dems won a lot of strong Remain votes in seats where they were out of the running.

A similar scenario could play out for the Greens. Their overall vote could go up, as they pick up more radical social and economic left wingers disappointed by Starmer’s moderation. But the prevailing anti-Tory mood will influence potential Green voters too. So I expect they’ll have some strong performances in safe Labour seats, while being heavily squeezed in marginal seats being defended by the Conservatives. For this election at least, I think we can expect Green voters to prioritise evicting Tory MPs. The result could be a bigger overall Green vote, but without this denting Labour’s election prospects much.

Step 3: A Scottish Labour surge

The trendline in Scottish polling since Nicola Sturgeon's departure as SNP leader has been very clear - the SNP are sharply down, and Scottish Labour is on the rise. There are good reasons to expect that to continue - Humza Yousaf is a much less popular and effective leader than Sturgeon was, scandal will continue to weaken the SNP as investigations into the party’s finances continue, and the general anti-incumbent mood may mobilise voters against the SNP in Scotland. They have after all been in charge at Holyrood for 17 years, even longer than the Conservatives have headed governments in Westminster.

Source: Wikipedia

In this scenario, the SNP to Labour swing has further to go, and Scottish Labour overtake the SNP in overall vote share - Scot Lab 36% (+17) SNP 33% (-12).³ A uniform 14.5 point SNP to Lab swing will net Scottish Labour over 20 seat gains. But these gains could go higher still. Firstly, Scottish Labour might achieve bigger swings in historically Labour areas of the central belt if latent Labour allegiances reassert themselves. Secondly, if we see anti-SNP/pro-union tactical voting by 3rd placed Liberal Democrat and Conservative voters in SNP-Lab seats. In this scenario, I predict at least one of these phenomena will be strong enough to boost Labour to 28 gains from the SNP, with the Liberal Democrats also regaining Jo Swinson’s East Dunbartonshire seat.

Step 4: Big swings where it counts - Labour sweep the battleground seats

All of that brings us to the main event - the Conservative vs Labour contest being fought mainly in the marginal seats of England and Wales. Let’s start with the aggregate vote shares for the two largest parties vying for government. Predictions so far imply a smaller total "big two" total vote share than we saw in the last two elections.:

LibDem24: 12 (n.c.)

ReformUK24: 10 (+8)

Greens: 4.5 (+1.7) SNP: 3 (-1)

Plaid & other minors: 2 (+1)

Total non ConLab: 31.5

Total Con & Lab vote: 68.5

My smaller party predictions therefore imply a return to the more fragmented pre-Brexit norm in voting - here are two party GB vote share totals since 1997:

Source: Election statistics reported in “The British General Election of…” academic studies

A fall in the “big two” vote share this year seems plausible to me for a number of reasons. The unifying force of Brexit is gone, so the longer term trends of declining partisanship and political fragmentation should reassert themselves. Electoral geography will encourage large tactical anti-Conservative voting in the many seats where Lab are out of the running, boosting support for the Liberal Democrats in particular. Enthusiasm for the “big two” overall is low - while a range of polling shows high voter hostility to the Conservative incumbents, the same polling often shows a lack of enthusiasm for Labour. The higher salience of immigration, growing perceptions that Brexit has failed and, in this scenario, the return of Farage will push up Reform on right fringe. Meanwhile, the higher salience of climate change, and left wing disgruntlement with Starmer’s moderate stances, will push up the Greens and perhaps others on the left fringe. A 68.5% combined vote for the big two next time would be bang in line with the level of big two voting in 2005-15, before the Brexit shock to the system.

The current polling is also broadly in this range. For example, Con 25 Lab 43.5 would combine to exactly 68.5. A lot of recent polls are in this ballpark. But while I expect the aggregate vote share for the big two to be roughly where it is now, I think the division of votes between the parties will be a bit closer come election day than it is now. Nigel Farage’s return will prevent the Conservatives from squeezing back ReformUK votes (something I expect will happen if Farage stays on the sidelines) but I think the Conservatives will recover some votes from Labour due to an improving economy and because some of the current “don’t knows” are just a lot closer to the Conservatives than Labour on most issues, and so will return to the fold. A 43.5% Labour vote share would be close to Tony Blair's 1997 showing. That feels a bit high - Blair in the late 1990s was by some margin the most popular leader of either party in polling history. Starmer is not matching those dizzy heights and, unlike Blair, he may leak some votes to the Greens on his left flank too.

So I'm going to project a slightly tighter outcome, with the Conservatives on 28 and Labour on 40.5. That completes the GB vote share predictions, producing an election result as follows: Lab 40.5 (+7.5) Con 28 (-16.7) LD 12 (n.c.) ReformUK 10 (+8) Greens 4.5 (+1.7) SNP 3 (-1) PC/Oth 2 (+1)

Vote shares 2019 (dark bars) and projected vote shares 2024 (light bars)

Source for 2019 vote shares: statistical appendix of “The British General Election of 2019”

This would be a 12 point Conservative to Labour swing, substantially larger than the 10.5 point swing Tony Blair achieved in 1997. This record swing would be driven in particular by a slump in Conservative support, accelerated by ReformUK’s Farage driven surge. The 16.7 point projected decline in the total Tory vote would be the largest ever fall in a party’s GB vote share, beating the record set by the Liberal Democrats’ post Coalition collapse in 2015. Labour's projected vote share increase of 7.5 points would, by contrast, be impressive but not record breaking. This would be a smaller rise than Tony Blair achieved in 1997, Clement Attlee achieved in 1945, or Jeremy Corbyn achieved in 2017.⁴

How would votes translate to seats in this scenario? Much depends on the pattern of tactical voting, as we can see by using Ben Ansell’s excellent election simulator (https://livedataoxford.shinyapps.io/GE24Simulator/) I will adjust results to reflect my Scotland prediction, which Ben's app doesn't calculate separately.

If we compute these vote shares and assume zero tactical voting, then we get (roughly):

Labour 351

Conservatives 221

Liberal Democrats 34

SNP 18

Labour majority of 52

If instead we assume a quarter of Labour, Liberal Democrat and Green voters vote tactically for the strongest local candidate⁵ we get:

Labour 360

Conservative 204

Liberal Democrat 44

SNP 18

Labour majority of 70

If we up the tactical voting further, assuming that half of Labour, Liberal Democrat and Green supporters vote tactically for the best placed party among the three we get:

Lab 370

Con 181

LD 57

SNP 18

Labour majority of 90

Labour are thus highly likely to emerge with a substantial majority in this scenario, but if there is also substantial anti-Conservative tactical voting, that majority goes up a lot. But I also think there are two other factors, not in Ben's model, which could push Labour's seat haul up yet further.

Firstly, Ben's model assumes uniform swing, but there are now good reasons to think the swing in the next general may not be wholly uniform. In recent local elections, Cons have done worse in the places they start strongest - a proportional swing pattern - see for example this article by Stephen Fisher and my analysis of the 2023 local elections on this substack

Secondly, Ben Ansell's model distributes extra ReformUK votes roughly uniformly across seats.⁶ But it is very likely ReformUK will do better - and therefore the Conservatives will do worse - in the 300 plus Conservative seats where the Brexit party didn't stand a candidate in 2019.

If we assume 50% tactical voting, there are about 50 England and Wales seats where Ben's model spits out a Con majority of 5 points or less. If we assume that proportional swing and/or higher ReformUK votes flip half of these seats to the second placed party we get the following outcome:

Labour: 388

Conservatives: 156

Liberal Democrats: 64

SNP: 18

Labour majority of 126.

I should make clear that this is a very basic and deterministic set of back of the envelope calculations based on a single scenario. These are all guesstimates, not a fully worked through model. I’m not attaching probabilities to any part of this outcome, instead it is intended as an illustration of one chain of plausible events which ends in a Labour landslide win. I think this is a useful exercise, both because this scenario is under-discussed and because laying out every step of the chain in this scenario makes it easier to identify the things which may or may not break Labour’s way. This helps us to know which indicators to watch as the election approaches.

Each link in the chain of events in this scenario is grounded in plausible interpretations of the evidence we have right now: Farage may well return; ReformUK is likely to do better if he does; Labour, Lib Dem and Green supporters have shown a strong willingness to engage in anti-Tory tactical voting in recent local elections (and, for the Lib Dems and Labour, in by-elections too); a big SNP to Labour swing is already there in polling and there are reasons to think it will grow further; unionist tactical voting was evident in the last Scottish Parliament elections and may return; some degree of proportional swing with the Conservatives doing worse where they start stronger is both plausible and again something already seen in local elections; and stronger Reform UK performances are very likely to hurt the Tories most in seats where there was no Brexit party candidate last time.

I'd be very surprised if every link in the chain came out exactly as predicted above. But while none of these things are certain, all of them are entirely plausible, likely even, based on what we know now. No miracles or heroic assumptions are required to generate a Labour landslide this year - just a continuation or intensification of existing trends plus a dusting of disruption from Nigel Farage. It probably won’t happen. But its certainly possible.

Postscript - 62 Lib Dems? You Cannot Be Serious!

When I posted this thread on Twitter and Blue Sky, I got a lot of incredulous responses from Liberal Democrats about the idea of 62 Lib Dem wins at the next election - matching the party’s 2005 high water mark. Liberal Democrats have endured many electoral disappointments and are thus by nature even more pessimistic than perenially gloomy Labour activists. But these responses also made a good point - the Lib Dems won’t target this many seats, and indeed couldn’t target so many seats even if they wanted to, given limited resources and a small activist base. All of this is true, and may indeed weaken the case for such a big Lib Dem seat haul. But it is worth bearing in mind that, in this scenario, many seats could fall even without a strong local Lib Dem campaign, due to a combination of a large Tory vote share decline, ReformUK splitting the Leave vote and some Labour/Green voters switching to the Lib Dems due to figuring out on their own that the Lib Dems are best placed to defeat the Tories locally. Perhaps one way to think of this total - like the Labour total - is as a plausible “best case scenario”. What the seats calculations do underline is one underappreciated legacy of the 2019 election - there are now a lot of seats where the Liberal Democrats are in second place to the Tories, and start strong enough that they can win if things beyond their control (Farage, ReformUK, tactical voting) break their way.

1. You can read the original threads here and here

2. Honourable exceptions include Lewis Baston and Sam Freedman

3. The first published draft of this had incorrect figures, which overstated Labour’s 2019 performance and hence understated the swing from SNP to Labour. My thanks to Graham Harries for pointing out the error quickly.

4. A statistic which we would no doubt hear a lot from Labour left wingers if such a scenario came to pass.

5. Ben Ansell’s seat calculator changes aggregate vote shares when you add in tactical voting. I am assuming these vote shares already reflect tactical voting so I had to do a bit of fiddling around with the starting shares to get this outcome, which is keeping the aggregate vote shares fixed at their starting point but adjusting the level of tactical voting going into this outcome.

6. Ben kindly gave me a full explanation of how his model generates ReformUK totals, as follows: “It does a UNS (Uniform National Swing) but with the obvious problem that they didn’t stand in some seats last time in which case they just get the average Reform vote. Obvs that’s not ideal. Might have been better to use UKIP 2017 or 2015 I suppose.”