Anti-Brexit opposition parties announced a plan this week to stand aside for each other in 60 seats across England and Wales at the upcoming UK general election.
The electoral pact, brokered by the group Unite to Remain, is designed to help the maximum number of pro-Remain candidates win seats on December 12 in order to prevent Prime Minister Boris Johnson from winning a majority and pushing through Brexit.
However, there is growing concern among pro-European campaigners that the alliance could inadvertently have the complete opposite effect.
Rather than stopping Brexit, they fear that the pact could actually help Prime Minister Boris Johnson and the Conservative party win seats and then push through the hardest possible form of Brexit.
The 'Remain Alliance' will target pro-Remain Labour MPs
Under the terms of the agreement, the Liberal Democrats will be given a clear run at 43 seats, including key target seats in London and the south of England.
Meanwhile, the Green Party will have a clear run at 10 seats, including Brighton Pavilion and the Isle of Wight while Plaid Cymru will be given a clear run in seven.
However, the choice of target seats has raised eyebrows among some pro-European campaigners, because many of them are already held by Labour MPs who are strong supporters of remaining in the EU.
Their fear is that in these seats the alliance will simply help the Conservative candidates, who are currently in second place, come through the middle and win.
A senior figure in the anti-Brexit movement said there was particular concern about four constituencies in particular: Exeter, Portsmouth South, and Stroud in the south of England, and Cardiff Central in Wales.
All four are held by Labour incumbents who support a “People's Vote” and staying in the EU. These are Ben Bradshaw (Exeter), Stephen Morgan (Portsmouth South), David Drew (Stroud), and Jo Stevens (Cardiff Central.)
All four are vulnerable to seeing their majorities overturned by the Conservatives if Unite To Remain candidates take away significant numbers of Remain-supporting voters.
For example, Labour's Stephen Morgan defeated the second-placed Conservatives by just 1,554 votes in 2017.
'This isn't the way to stop Brexit'
Pro-European Labour MPs on Friday spoke out against the alliance on Friday.
“I've long championed the idea of a progressive alliance, and there is a strong case for parties working together given our electoral system,” Labour MP Clive Lewis said on Friday.
“But this Remain alliance risks taking votes away from Labour in marginals and targets good, sitting pro-remain Labour MPs.
“This could give the Tories the advantage in certain areas. It is irresponsible. I urge the parties involved to talk to Labour and reassess.”
Lewis' colleague Chi Onwurah reiterated this, saying: “This isn't the way to stop Brexit. We need to see pro-remain Labour MPs return to parliament, and in key Labour-Tory marginals, we need as much cooperation as possible. The remain alliance announced yesterday risks doing the exact opposite of what it intends to do, providing a boost for Tory Brexiteers in tight marginals.”
—Ben Bradshaw (@BenPBradshaw) November 7, 2019
Despite this criticism, the Liberal Democrats have defended the decision to target Labour Remainers, saying that Jeremy Corbyn's party is not explicitly in favour of remaining in the EU. They also point out that Labour have point-blank refused to be involved in the alliance.
Lib Dem party president Sal Brinton told Business Insider on Thursday that she “would have loved” to have worked with Labour Remainers had they chosen to.
Unite to Remain's Pete Dunphy said that the group had approached Labour in the early days of the campaign, but was “heavily rebuffed” by members of the Shadow Cabinet.
A senior Lib Dem source told Business Insider: “Not only are Labour Remainers standing on a national platform and for a leader refusing to back Remain, but their party refuses to stand down for us or any other Remain party anywhere — not only is that policy, it's written into their party rules.”
A separate tactical voting initiative by the pro-EU group Best For Britain have previously estimated that electoral pacts could stop Conservative candidates winning in up to 158 constituencies. This is around a quarter of House of Commons seats.
However, crucially, Best for Britain's analysis was based on pro-Remain opposition parties standing aside for Labour, and vice versa. This will not happen under the Unite to Remain plan.
Voters may refuse to transfer their vote
There are also doubts among campaigners about how effective the alliance will be in persuading voters to back Remain parties.
YouGov research published before this year's European Parliament elections found that just 37% of Green voters would support a Remain alliance candidate.
This means that in seats where Green candidates have stepped aside for the December election, Green voters are far from guaranteed to move to another Remain alliance party.
They may instead opt to back Jeremy Corbyn's Labour or simply not vote at all.
Overall, the anti-Brexit movement and its political parties have welcomed Unite to Remain as a significant and positive achievement. There was some surprise that the group was able to strike agreements in as many as 60 seats.
There are also seats where it will likely be fruitful. In Cheltenham, for example, the Lib Dems are just 2,569 votes behind the Conservatives, and the Green party's decision to step aside could help the party take the seat.
However, in a general election which is so unpredictable, there is a growing fear that the Unite to Remain experiment could go badly wrong.