There’s been a lot of soul searching within the Labour Party since last week’s election. Why did they face their fourth consecutive defeat at the ballot box, and fall to their lowest number of seats since 1935?

To try and better understand what went so wrong we have spoken to nearly 500 voters since the result who voted Labour in 2017 but defected this time. Given that Labour’s vote share fell by nearly 8%, this was clearly the key dynamic of the campaign, and understanding why these voters left might help the party better understand how they can win them back.

Voters had clearly gone off Jeremy Corbyn

The biggest reason for defection, mentioned by 35% of those surveyed, was Jeremy Corbyn and his leadership. Most people didn’t expand on this, just mentioning the leader by name. This is consistent with the drop in Jeremy Corbyn’s favourability we have seen since 2017 and has clearly alienated voters.

In our first poll after this election just 21% of voters had a favourable view of the Labour leader, compared to 46% who did so straight after the election in 2017.

Brexit created difficulties for the Labour campaign

Brexit was close behind the leadership issue, with one in five (19%) saying it was their main reason for defecting.

Whilst it is clear that support for a second referendum was a large part of this, and there were twice as many Leavers who defected over Brexit than Remainers, that isn’t the whole story.

Firstly, because there was still a substantial minority of voters who still left the party because they didn’t believe the party to be Remain enough.

But also because of the way that the party’s view on Brexit interacted with views of the party’s leadership. When we polled earlier in the year on why they were going off the Labour leader, the main responses were around Brexit.

The data then showed that it wasn’t just due to his position being too far towards Remain (just 3% thought this) or too far towards Leave (just 6% said this), but rather the fact that he doesn’t seem to have any position at all - making him look weak and indecisive.

In total 13% of respondents mentioned that he had been too weak on Brexit, and not taken a decisive stance.

That message is clearly coming through again in this latest data, with many people saying that they felt the party looked weak because of the decisions they had made on Brexit.

But the party clearly struggled with other policies as well

With Brexit dominating the discussion so far, it is also important not to forget the importance of other policy areas, which was mentioned by 16% of those who abandoned Labour.

In most cases, this was to do with the economic policies proposed in the manifesto and a feeling this time around that they are undeliverable and would cost too much.

This is consistent with polling before the election, which showed that the majority (63%) thought that Labour’s policies are not realistically deliverable, and that the party would not deliver on its promises.

A significant minority left Labour to vote tactically

The final significant element that lead to a drop in Labour’s vote share is tactical voting. There was a lot of discussion of tactical voting in this campaign, with pro-Remain websites pushing people towards it in order to stop Brexit.

In total, 10% of voters said this was the main reason they didn’t vote for Labour this time around. Unsurprisingly, this rises to 15% among Remain voters who left, but is the main reason for just 3% of Leave voters who left.

These voters will almost all have been in seats which Labour didn’t have a hope of winning anyway (because of the nature of tactical voting) so will not have made a substantial impact on the result.

Image: Getty