A LEFT-WING think tank has said that the Labour party has almost no chance of securing a majority in the next general election unless it forms an alliance with the SNP and the Liberal Democrats.

The Fabian Society, which has traditionally had strong ties with Labour, said it is “unthinkable” that Jeremy Corbyn’s party will win enough votes to govern alone and urged the flailing party to consider forming a coalition with the SNP and LibDems.

The report says Labour could expect to win fewer than 200 seats at its current poll ratings (27 to 28 per cent), but warned that the party could be left with as few as 140-150 MPs if, on election day it was to underperform on its mid-term polling – as it traditionally does – by about eight per cent.

Its only hope of government in either case would be to work with other progressive parties to keep out the Tories. But Scottish Labour immediately said they could not support any alliance with the SNP, claiming there was “nothing progressive about the party” and refused to support a second independence referendum.

A Scottish Labour spokesperson said: “Labour is a socialist party. The SNP most certainly isn’t. The driving force behind Labour is the desire to help people get on in life, no matter their background. It’s about people, not a line on a map.

“There is nothing progressive about the SNP, which seeks to harm our economy by breaking away from our biggest trading partner. That’s why there will be no support from Scottish Labour for a second independence referendum. Under the SNP, Tory austerity is simply being passed on in Scotland, with the Nationalists planning a £327million cut to valued local services in 2017. That is not progressive – it is a budget a Tory Chancellor would be proud of.

“If Labour is privileged enough to be in a position to put a programme for government in front of MPs in the future, SNP MPs will have to choose to support a Labour or a Tory government.”

The SNP responded by saying no party that was truly committed to delivering progressive politics would contemplate for one minute letting the Tories back into office, rather than work with the SNP.

“Labour lost the plot and the last election when they appeared ready to allow the Tories to remain in power rather than take up the chance of forming a progressive alliance in the Commons. What we saw in 2015 was Scotland voting to put its trust in the SNP to make Scotland’s voice heard – a clear voice for an end to austerity, better public services and more progressive politics at Westminster,” added an SNP spokeswoman.

Former Liberal Democrat MP John Leech, who snatched Labour’s safe seat of Manchester Withington in 2005 with the biggest swing in the country, said the party would struggle to support any alliance with Labour given its “vague and ambiguous position during the referendum”.

Britain’s oldest political think-tank, which produced the controversial paper, entitled Stuck, after analysing polling and election data, suggests that Labour is likely to win between 140 and 200 big city and ex-industrial constituencies on as little as 20 per cent of the vote, which would be a further retreat from the 231 seats it currently holds.

It said Labour must position itself in the centre-ground, as it is losing as many votes to the pro-EU Liberal Democrats as Ukip and the Tories, meaning it must find a way to appeal to both Remain and Leave voters in a political landscape now defined by Brexit. But the “firebreak” of the UK’s first-past-the-post electoral system would mean that their position as the main opposition party would not be in jeopardy, and could still have a platform on which to rebuild.

The Fabian Society has recommended that it should consider calls to form an alliance with the Lib-Dems and SNP or other centre-left parties as the UK’s political system continues to fracture.

Fabian Society general secretary Andrew Harrop said: “As things stand Labour is on track to win fewer than 200 seats, whether the next election comes this year or in 2020.

“Even if Labour recovers it has almost no chance of securing a majority in a general election, because it needs over three million more votes than the Conservatives to win. Labour’s aim for now should be to move forwards not back and win enough MPs to be able to form a governing partnership with other parties.”

The report says that Labour is too weak to win the next election whether it happens this year or in 2020 and only a little over half of the party’s 2015 voters say they support the party today. “Just like for the US Democrats, winning the popular vote is not enough for Labour,” Harrop added. “To win a majority of one the party needs to beat the Conservatives by a higher margin than it achieved at the time of its resounding 2001 victory and secure over 3 million more votes than the Tories. Even before Labour’s current problems, this was unlikely. It is currently unthinkable.”

He went on: “In Scotland, [with] the rise of the SNP and the collapse of Labour, on current polling the party would win zero seats compared to 41 in 2010.”