More than 100 pro-EU groups have sent a letter to Liberal Democrat leader Jo Swinson asking her to back Labour in the prime minister’s constituency.
The letter promises that if the Lib Dems step back in Boris Johnson’s constituency of Uxbridge and South Ruislip, the grass roots groups will then pile pressure on Labour to pull back in Esher and Walton, where Lib Dem candidate Monica Harding is up against foreign secretary Dominic Raab.
The 134 groups that have signed the “Boot Out Boris” letter “want to change the dynamics of the election”.
The letter to Swinson says: “We know we are asking you a lot to help Labour without any reason to think Jeremy Corbyn will return the favour. But if Johnson wins a majority, he’ll drag us out of the EU. So we implore you to look to the national interest.
“We also know you are already only running a paper candidate in Uxbridge. But we want you to go further and support Labour there.
“A similar letter is being sent to Corbyn asking Labour to support the Lib Dems in Esher and Walton, where you can bring down Dominic Raab.
“But to be clear, we don’t want you to wait for him to say yes. Time is terribly short, so we want you to take unilateral action.”
It adds: “To boot out the Tories, we have to vote tactically for the candidates with the best chance of beating them. If you step back where you don’t stand a chance, that message will be heard loud and clear across the land.”
Signatories include Devon for Europe, Sixteen Million Rising, British in France, Yes to Europe, Wales for Europe and Women for Europe.
Alex Pilkington, chairman at Devon for Europe, said: “If the Lib Dems and Labour pull back in key seats, this will supercharge the message that we need industrial scale tactical voting.
“With that, we can deny Boris his majority, get a referendum and stay in the EU.”