The Liberal Democrats have been criticised—even by their own members—for standing candidates in Labour-held seats where they appear to have little chance of winning, potentially splitting the pro-referendum vote.
With the nomination deadline for candidates now passed, the prospects for a formal electoral pact have also gone. Therefore, the outcome in these seats will come down to any tactical voting by individual voters.
So how willing might Lib Dem voters be to put aside their party preference and help Labour win?
I assume that to be prepared to do so Lib Dem voters must have a reasonably favourable view of Labour: as the chart below shows, around 43% of Lib Dem voters at least didn’t dislike the party when the latest British Election Study survey was conducted in June 2019. (I discuss the possibilities for Labour transfers to the Lib Dems later).
If we take this share of the projected Lib Dem vote in each seat in England and Wales, we can get a rough idea of where and by how much Lib Dem tactical voting might help Labour.
To do this, I use the MRP poll commissioned by the pro-Remain Best for Britain campaign group, conducted by focaldata.
I use three criteria to define which seats to look at. First, I take seats which Labour are less likely to win on their own, i.e. where they are two percentage points or less ahead of, or behind, the Conservatives in the focaldata poll. This allows for a margin of error.
Second, I look at seats where 43% of the Lib Dem vote added to the Labour vote would allow Labour to retain (where they would otherwise lose) or win the seat. This assumes that the remaining 57% of Lib Dem Remain voters wouldn’t then vote Conservative.
Third, I only include seats where the combined Labour-Lib Dem vote share is at least two percentage points above the Conservatives, again to allow for a margin of error.
This doesn’t include seats where the ‘Remain Alliance’ (the Lib Dems, Greens and Plaid Cymru) have agreed to stand aside for one another.
Nor does it include seats where we can expect a genuine fight between Labour and the Lib Dems, such as Battersea, Chipping Barnet and Sheffield Hallam.
Finally, seats that either Labour or the Lib Dems would win anyway without the other’s help according to the poll are excluded.
The result is that a 43% share of Lib Dem transfers would allow Labour to retain 38 seats that would otherwise be lost on current voting intention.
Most of these seats are those being targeted by the Conservatives as ‘Labour heartlands’ in the North, Midlands and Wales, where the Lib Dems have little chance of winning.
In this sense, it would be entirely defensive for pro-second referendum parties. There is no seat that Labour would gain owing to these transfers.
The seats retained are listed in the table below.
Could Labour tactical voting work the other way in favour of the Lib Dems?
First, we need to know how many Labour voters might be inclined to lend their vote to the Lib Dems.
As the chart above shows, around 60% of Labour voters had a reasonably favourable view towards the Lib Dems.
Repeating the exercise carried out above, the results appear somewhat underwhelming for the Lib Dems. As the table below shows, the party would stand to gain eight seats.
However, as the UK in a Changing Europe has pointed out in our analysis of the Remain Alliance, six of these might be winnable for the Lib Dems without Labour voters and with the support of Green voters alone.
It is therefore more like two seats that would be added to those yielded by the Remain Alliance: Hazel Grove, which our analysis suggests the Remain Alliance would struggle to win alone, and Wimbledon.
A constituency poll for Wimbledon published by Delta Poll this weekend suggested that such transfers to the Lib Dems might already be taking place.
Our analysis suggests that tactical voting by those who might be prepared to lend their support to the better-placed of Labour and the Lib Dems could make the difference in 40 seats.
If some of these voters stick with their first preference, those seats could stay or turn Conservative.
Alternatively, if the Lib Dem voters (71% of them) who say Brexit is the most important issue to them put their party preferences to one side and lent their votes to Labour, this could add a further 34 seats to their post-election coalition—with Labour gaining 13 seats on top of a further 21 holds.
This is perhaps unrealistic.
But it is clear that if pro-referendum voters can break through party boundaries, it could have a decisive impact on the final tally.
If they can’t, Labour are vulnerable to the Conservatives in dozens of seats, which would more than offset any gains the Remain Alliance might make elsewhere.
By Matt Bevington, policy researcher at The UK in a Changing Europe.