Thread by @robfordmancs

So Nigel Farage is in Bolsover today, making the now familiar "Brexit Party parking their tanks on Labour lawns" args. So lets' use this to have yet another look at those infamous Labour Leave seats. Here's estimates from @kevcunningham on how the 2017 vote in Bolsover broke down

You will see that in this 70% Leave seat, Labour's vote is in fact only 45% Leave - the rest is Remain (42%) and did not vote (13%). So, reiterating a point followers of mine will be familair with - most Labour voters in Labour Leave seats are in fact *not* Leave voters

But how would a strong BXP showing alter things here? Lets' work it through. For simplicity, lets' allocate the "did not vote" votes in the same proportions as the rest of the party's vote (this is friendly to Leave as "did not/could not votes tend to lean a bit Remain)

This (plus rounding for simplicity) gives us roughly the following starting groups of voters:
Lab/Remain: 12k
Lab/Leave: 13k (total Lab: c.25k
Con/Remain: 3k
Con/Leave: 16k (total Con c.19k)
UKIP/Leave: 2k
LD/Remain: 1k

To start with, lets' just give the BXP the whole UKIP vote, and leave the LD vote where it is for now. Now where will the extra BXP votes come from? Not from Remain, obviously, so Lab's 12k Remain vote will be unaffected by BXP standing (as will Cons' 3k Remain vote)

Instead, the *whole* impact of BXP has to come from those Leave slices. Lets' test out two popular theories: 1. BXP hurts Lab prospects by winning outright 2. BXP hurts Lab prospects by winning Lab leave voters Cons can't.

Farage's believes he can win in such seats, where Cons couldn't. How well would he have to do? Imagine BXP take 2 Leave votes from Con for every 1 Leave vote they take from Lab. UKIP got 9k here in 2015, BXP need to do better to be in contention.

They start with 2k from UKIP. Give them 8k from Con Leave (50% of Con Leave vote), and 3.5k from Lab leave (c.25% of Lab Leave vote). What happens?
Lab/Remain: 12k
Lab/Leave: 9.5k Lab total: 21.5k
Con/Remain: 3k
Con/Leave: 8k Con total: 11k
BXP/Leave: 13.5k

Lab win by 8k

So *even if* BXP takes *half* the Con Leave vote, they are *nowhere near being in contention*. Winning half the total Lab leave vote too wld still leave them behind. In order to win outright in seats like this, BXP party need a massive Leave vote share from a standing start

OK, how about scenario 2: "BXP is a threat to Lab because it is more attractive to Lab leavers". Plausible hypothesis, but what happens when we run the numbers? Lets take the opposite proportions - BXP now take 2 Lab Leavers for every Con Leaver.

Lets' say BXP takes half of Lab leave vote and 25% of Con Leave vote. That amounts to winning over 6,500 Lab Leave votes and 4,000 Con Leave votes (Con leave total is a lot more than half because *starting* Con leave total is much larger

Where does that leave our totals:
Lab/Remain: 12k
Lab/Leave: 6.5k Lab total: 18.5k
Con/Remain: 3k Con/Leave: 12k Total 15k
BXP/Leave: 12.5k

Lab win by 3.5k

So this scenario is closer, but even with the BXP taking *two* Leave votes from Lab for every *one* they take from Con *and* taking a hefty 12.5k total vote, Lab still win reasonably comfortably.

Note that in all of this we have not moved any Remain votes around. In the second scenario, more than two thirds of Lab's vote is coming from Bolsover Lab Remainers. If a quarter of them were to defect to LDs Lab would be in trouble.

Conversely, if Lab were able to convince more of the 4k Bolsover Con or LD Remainers that they were the only party who could stop a Tory Brexit, that adds to their cushion.

But wait! There's more! All through this we have assumed that Lab Leave voters will defect to BXP but not to Con. Some voters will vote BXP but never Con. But some would switch to Con in absence of BXP, but will back BXP in preference to Con if they get the chance.

What I hope this exercise helps illustrate is that even in a 70% Leave Labour held seat, it is no simple matter for the BXP to win directly or to help Con indirectly. To win directly, they need a huge swing from Con Leavers.

While to tip the balance to Cons would require BXP recruitment to skew very, very heavily towards Lab Leavers *and* for the Labour Leave vote to be strongly dominated by voters who would back BXP but would never back Con.

Notice also that this means Con and BXP incentives are in opposition. If Farage wants his candidates to win, he has to hurt Cons because that's where the Leave votes he must consolidate are. If Cons want BXP to hurt Lab they need a weak BXP candidate focussed on Lab votes

So while I'm sure it is possible for seats to exist where the BXP vote is both very large and hits Labour harder, I think people are failing to consider how many chips have to fall just right for this to be true

Tl:dr - its really hard for BXP to hurt Lab prospects in Lab Leave seats unless they do a lot better with Leave voters than current polling suggests or the votes they pick up skew much more strongly to Lab than current polling suggests. Not impossible. Just really hard.

(and even in Lab Leave seats like Bolsover what happens with the Remain minority is also really important. If Lab Remainers go LD, life gets harder for them. If LD and Con Remainers go Lab, life gets easier) /END/

(incidentally, I have talked only here about the effect of BXP, not the chances of Con winning the seat from Lab directly. Easiest way for them to do that is to win Lab Leave votes directly. Intervention of BXP will usually make that harder, not easier)