Every Scottish constituency will be a marginal seat at the next general election, polling expert Professor Sir John Curtice has said. 

The Strathclyde University psephologist was speaking as a new poll put Labour and the SNP on near-level pegging ahead of the Westminster vote, widely expected next year. 

Survation found support for Anas Sarwar’s party at 35%, while Humza Yousaf’s took 37%. The Tories were on 17% and the Lib Dems on 6%.

Prof Curtice's analysis suggests this would give both Labour and the SNP 24 seats, while the Conservative would take six, and the Lib Dems five. 

Though this is based on the current constituency boundaries which are due to change at the next election. 

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"There's certainly is all to play for so far as the representation of Scotland at Westminster at the next general election with potentially important implications for the overall outcome of the next UK General Election," the academic told an online briefing hosted by True North, the political consultancy who commissioned the poll. 

He said that even very small swings in the run-up to an election could have a major impact on the number of seats won by each party.

The Herald: First Minister Humza Yousaf chats with local Yvonne Boyle and granddaughter Rosie Liddell whilst campaigning in Rutherglen and Hamilton West

"Pretty much every seat in Scotland will be a marginal seat, and therefore a relatively small increase in the SNP lead, and all of a sudden those high expectations for Labour would not look quite so realistic.

"But equally, if the Labour Party could actually overtake the SNP in voting intentions in Scotland, something they've not yet managed to do according to any poll, then they could indeed, quite clearly be the dominant party so far as Scotland's representation at Westminster is concerned."

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Prof Curitce said that if the poll was reflected at the next election, Sir Keir Starmer would "be delighted."

"It could mean Labour picking up two dozen seats in Scotland, and if Labour picks up two dozen seats in Scotland, you can probably knock four points off the lead over the Conservatives the Labour Party would need UK-wide in order to achieve an overall majority."

He said the arrest of the party's former chief executive Peter Murrell and then of the then SNP treasurer Colin Beattie "basically didn't make any difference to the SNP position in the polls."

It was the bitter and divisive leadership contest that did the most damage. 

However, he said there had been a notable decline in the polls since the arrest of Nicola Sturgeon. 

The three party figures were questioned by detectives as part of a probe into the SNP's finances. They were all released without charge pending further investigation. 

As well as the arrests, the home Ms Sturgeon and Mr Murrell share was raided by police, and a luxury motorhome was seized from the driveway of Mr Murrell's elderly mother. 

"The arrest of Sturgeon did just discombobulate some SNP supporters in the way that the initial arrests and the initial publicity given to the SNP did not," Professor Curtice said. 

"Now of course, we then also should bear in mind, the SNP is definitely exhibiting some of its nervousness and some of its internal dissent in public."

That said, he added, there was not much sign that the internal disagreements and disputes within the SNP and within the Scottish Government coalition "might have meant that the SNP lead over Labour, narrow as it is, would have narrowed significantly further."

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On the Holyrood list vote, the poll showed that both the SNP and Labour were on 30%. The Tories were on 15%, and both the Lib Dems and Scottish Greens on 9%.

On the Scottish Parliament constituency vote, the SNP were on 39%, while Labour was on 34%. The Tories were on 16% and the Lib Dems on 8%.

Despite the SNP’s fortunes waning in recent months, support for independence remains stable at 48%, while no remains at 52%.

The poll also showed that 28% of Scots support the Bute House Agreement, while 40% oppose.

Back in May, 57% of 2019 SNP supporters voted for the deal, it's now down to 48%.

Scottish Labour Deputy Leader Jackie Baillie welcomed the survey: “This latest poll shows once more that change is coming to Scotland with Scottish Labour. “While the only poll that matters is polling day, it’s clear that after a decade of SNP dominance it’s now neck and neck between the SNP and Scottish Labour.

“While the SNP offer only division and sleaze, Scottish Labour is offering the change and fresh start that Scotland needs.

“From creating thousands of green jobs to tackling the cost of living crisis, only Scottish Labour is listening to the concerns of the people.”