LABOUR supporters in England would be "appalled" if their party allowed Theresa May’s Conservatives back into government and rejected a "progressive alliance" with the SNP, Nicola Sturgeon has claimed.

With the opinion polls narrowing in the run-up to June 8, the Nationalist leader said it was "no longer inevitable" Mrs May would be returned as prime minister with an increased majority.

Ms Sturgeon explained: "If there was to be a hung parliament, if the parliamentary arithmetic allowed it, then I would want the SNP to be part of a progressive alternative to a Conservative government.

''Not in a coalition, I don't envisage any formal coalitions, but on an issue-by-issue basis to put forward progressive policies and to see a progressive agenda."

The First Minister went on: “Many people south of the border would be appalled at how Scottish Labour is behaving, where they seem to be more determined to somehow stop the SNP than they are to stop the Tories, which would be inexplicable to most people in the Labour Party south of the border."

With some reports suggesting pro-Union parties in Scotland are working together to defeat the SNP by limiting campaigning in some areas, Ms Sturgeon said: "It is shameful that Labour appear to be in cahoots with the Tories in Scotland.

"Instead of working to hold a Tory government in check, you have Scottish Labour appearing to be in talks with the Tories or appearing to be in informal arrangements with the Tories to boost a Tory majority. Most people would be appalled at that.”

She added: "As this campaign has gone on, more and more people have seen what the consequences of a Tory government with an increased majority would be and they don't like that."

Earlier, the SNP leader suggested that if the Prime Minister was returned to power but with a small majority, then Scotland could become pivotal and take centre stage in British politics.

She told BBC Radio 4’s Today programme: “My reading of the polls says that Theresa May and the Tories are still on the track to win this election but they are no longer certain to get a bigger majority in this election and in that scenario Scotland becomes centre stage and, potentially, has a pivotal and decisive role to play because it could be the case that what determines whether or not Theresa May has a bigger majority is the outcome of the election in Scotland and that’s my key message."

Meantime, Kezia Dugdale insisted that there would be "no need to negotiate" with the SNP because the Nationalists would face the prospect of backing a minority Labour administration or "letting the Tories back in".

The Scottish Labour leader said: “The reality is that in a minority Labour administration situation there would be a Labour Budget underpinned by the commitments we have in our manifesto and it would be there and presented for the SNP to either vote for or vote down.

"In that situation, if they vote for it, great that's what will be delivered, if they vote against it we would find ourselves in a position where we would have a Tory government all over again.

"So, there is no need to negotiate with the SNP. It is down to them to either live by their anti-austerity credentials that they are so keen to talk about or let the Tories back in."

However, opponents think once in power Labour would not want to relinquish it and, given the pressured backdrop of the Brexit talks, Jeremy Corbyn – who has already signalled he would allow a second Scottish independence vote – might be forced to offer some form of informal deal to smooth the passage of his new administration.

But asked if a second independence poll could become a bargaining chip in such a scenario, Ms Dugdale replied: "Categorically not, we've made it abundantly clear in our manifesto that we think a second independence referendum is unnecessary and unwanted."

The Scottish party leader, who once said she did “not think Jeremy can unite our party and lead us into government,” endorsed the UK leader, saying she was not surprised by his progress in the polls.

"He is that authentic voice; people like that he is not a scripted politician, that he says what he thinks," she declared.

"Given 20 minutes to freestyle, he can give you an impassioned take on Labour values and the difference that a Labour government can make. That's why when he does a 10-second TV clip sometimes he gets himself into a little bit of difficulty, in your eyes not mine, but the reality is people like what they see," added Ms Dugdale.