The local Green party will meet tonight to decide if they should field a candidate in the general election in Lancaster and Fleetwood.
The vote comes after senior Labour and Green party figures wrote to each other trying to broker an electoral pact to stop the Conservatives.
In a letter to the North Lancashire Green Party (NLGP), Labour candidate Cat Smith said she was pleased at calls for a “local progressive alliance” between Labour and the Greens.
She also said she had been approached by many Greens who wanted to see her re-elected as MP.
But a leading Green said it was clear Labour didn’t want an alliance and instead just wanted the Greens not to stand in Lancaster.
And Eric Ollerenshaw, Conservative candidate in Lancaster and Fleetwood, said the Greens declining to contest the election would be “a mistake”.
The Green Party has chosen candidates for Lancaster and Fleetwood, and Morecambe and Lunesdale but have not officially confirmed them.
An announcement either way is expected after Tuesday night’s vote.
Gina Dowding, the Greens’ only Lancashire county councillor, said there were reasons why the Greens should stand in Lancaster and Fleetwood.
“Standing aside in an election where we have a strong presence will look very weak to the public unless there was some concrete deal that would benefit us in some way electorally - to increase our chances elsewhere,” she posted on the North Lancashire Green Party Facebook page.
“This is especially true in an area where the Greens have city and county councillors. We would be denying a democratic right to those people who fundamentally want to vote Green a chance to vote.”
But others have posted on the NLGP Facebook page calling on the Greens not to stand on June 8.
Richard Twine wrote: “As a long standing Green voter locally my opinion of the local party will plummet if you field a candidate against Cat Smith.
“It will be 2010 all over again. With much of the local UKIP vote (which was much larger than the local 2015 Green vote) returning to the Tories now it makes sense for the local Green Party to support Cat Smith, who has higher green credentials than most Labour MPs and of course supports PR.”
Ms Smith, writing in response to a letter from the NLGP, said: “I was pleased so many wanted to have a conversation about a local progressive alliance for this snap general election where you would support me to be re-elected by not standing a candidate.
“I know that many members of the Green Party, like the Labour Party, recognise the threat a Conservative government poses to our community across Lancaster and Fleetwood. “Given the very marginal nature of our constituency, where just 700 people voting differently two years ago could have resulted in us having a Tory MP, we probably realise this more than most.
“We often find ourselves supporting the same campaigns and issues both locally and nationally. From standing side by side at anti-fracking demonstrations to supporting local homeless people, foodbanks (although we’d both agree with better government policies we wouldn’t need them!) to May Day demos to opposing NHS privatisations, our members find themselves on the same side of the argument when it comes to many of the big issues.”
In their letter to Ms Smith, the Greens made two requests before they would consider standing aside.
They want to see a firm commitment in the Labour Party manifesto to introducing Proportional Representation in the House of Commons, and for the Labour leadership to talk with the Greens about a possible electoral alliance that would consider both parties standing aside in some seats.
In response, Ms Smith said: “I support Proportional Representation... I will be pushing the case for this to form part of my party’s manifesto in the coming days.”
Ms Smith has put her name to a new report endorsing PR - an electoral system in which parties gain seats in proportion to the number of votes cast for them as opposed to the current ‘first past the post’ system.
But on the second request, Ms Smith said: “I can only honestly make commitments in areas I have control over - and this is not something which is in my gift to give. All I can say, is that my politics is one which is deeply rooted in environmentalism.”
Coun Dowding said: “Our understanding of an alliance is that there is give and take.
“Since our letter was sent (and hearing constant messages from Labour leadership nationally that they will not broker any deals) I still tried to seek some sort of electoral pact here in Lancashire: to see whether it would be possible for Labour, for example, to stand aside for our candidate in the Fylde, Tina Louise Rothery, and hoped to begin to broker some sort of reciprocal arrangement.
“It is clear that Labour are not interested in any form of alliance. What they want is the Greens to stand down.
“This will be debated at our meeting tonight.”
The two sides disagree over who made the first move over the alliance.
Coun Dowding said the Greens’ letter was sent in response to Labour approaching them, but Ms Smith said she was contacted first by the local Green party.
Eric Ollerenshaw, Conservative candidate in Lancaster and Fleetwood, said: “I think this could be a mistake for the Greens to consider, as we all know how unforgiving the voters can be - just look at what happened to the Liberals in 2015.
“The real shame is that the Greens have done a great job in bringing the environmental agenda to the fore for all political parties by their principled stance and by entering into this coalition they run the risk of throwing that away.
“Will the voters of the future now think that a vote for the Green Party is just a vote for Labour?”
Lancaster and Fleetwood was a marginal seat at the 2015 election, with Ms Smith winning for Labour by 1,265 votes from Eric Ollerenshaw of the Conservatives.
The Greens came fourth, with Chris Coates polling 2,093 votes, behind the UK Independence Party who got 4,060 votes.
But with experts predicting that a chunk of UKIP votes may go to the Tories on June 8, Labour, Green and Liberal Democrat activists have been uniting in other parts of the country hoping to form a progressive alliance.
In some constituencies, including Ealing, Hove, Ilford, Oxford West and Abingdon, and Richmond Park and Twickenham, the Greens will not field a candidate.
Some Labour members have called for their candidates to stand aside in the Isle of Wight and Brighton Pavilion, where Green leader Caroline Lucas was her party’s only MP. The Lib Dems have already stood down in this constituency.
However, both Labour and the Liberal Democrats have ruled out this kind of alliance on a national scale.
The Liberal Democrats have said deals may be agreed on a local basis, while the Labour leadership has refused to enter into any kind of tactical pact.
We have approached Robin Long, Lib Dem candidate in Lancaster and Fleetwood, for comment.
UKIP are not expected to field a candidate in Lancaster and Fleetwood on June 8.