BORIS Johnson's exit will not lead to a reduction in support for independence or the SNP, according to a leading pollster.

Mark Diffley, director of the Diffley Partnership and a former director of Ipsos MORI in Edinburgh, said a new Conservative leader was unlikely to alter voters's views on Scotland's constitutional future.

Mr Johnson announced his resignation as leader of the Conservative party on Thursday though he intends to stay on in Downing Street as a caretaker Prime Minister until a new Tory chief is elected over the summer.

The Prime Minister has regularly been described by commentators as a "recruiting sergeant" for independence with the SNP often focusing on his unpopularity in Scotland as part of their strategy to drive up support for independence.

Tory MSP Murdo Fraser tweeted a picture of a baby crying when news broke of Mr Johnson's resignation, writing "Live scenes from SNP HQ".

One Scottish Conservative insider told The Herald on Sunday: "The SNP, like Labour, will be devastated by Boris Johnson resigning."

But Mr Diffley said that opinions on independence was now so entrenched that his exit would be unlikely to shift opinion significantly.

"I don't think his resignation will have a huge impact on support for independence," he said.

"The caveat, of course, would be who comes next and what their position will be. I don't expect anyone thinks that the successor's views will be radically different on independence or on the timing of an independence referendum."

Mr Diffley said Mr Johnson's successor would keep to the position adopted by the Conservatives that there are more pressing issues, such as the cost of living crisis, the recovery from Covid and the war in Ukraine, to focus on rather than independence - a stance underlined by Scottish Tory leader Douglas Ross.

He added the new Conservative leader would try and build bridges with the Scottish Tories after relations became considerable strained with the UK party during Mr Johnson's Downing Street career.

"They would be taking on board what Douglas Ross's position is on a second independence referendum and listening to him. He's not going to change his view, so that means that the new leader is not going to take a different approach even if they were minded to," he said.

"That line - that it's not the time - will be put forward even more strongly in the future and the new UK Conservative leader will want to prop up the Tories in Scotland," said Mr Diffley.

"Despite Johnson being massively unpopular up here and being seen as something of a recruiting sergeant for independence, we haven't seen support for independence massively increase during his tenure."

He said that at the height of the Covid pandemic support for independence rose (to 58 per cent) based on voters having a higher regard for the First Minister's actions than the Prime Minister's.

However, since then it has fallen with the latest poll by Panelbase, published in the Sunday Times last weekend, putting support for independence slightly ahead on 48 per cent compared to 47 per cent being in favour of the union.

"I'm not sure whether it was actually the case that he was the biggest recruiting sergeant for independence," he said.

Asked if a new leader, seen as more conciliatory, may reduce support for independence, he added: "There might be at the margin but opinion is so entrenched that a slightly more conciliatory Prime Minister isn't really going to have a huge impact on support for independence or the SNP."

The First Minister last month unveiled her route map for Indyref2 if the UK Government continued to fail to agree to a new referendum.

She wrote again to Mr Johnson to request that powers are transferred from Westminster to Holyrood to hold a legally binding vote via a Section 30 order of the Scotland Act.

As a back up plan she said she intended to use devolved powers to hold the vote on 19 October 2023 if her legislation to do so was ruled as lawful by the Supreme Court.

If it is not ruled to be within Holyrood's powers she said she would use the next general election as a "de facto" referendum on independence and would regard the SNP winning more than 50 per cent of the total votes cast as a mandate.

Mr Diffley said that even with Mr Johnson gone, he believed it would be possible for the SNP to exceed achieving over half the share of the total vote.

However, he said the goal would require that the other pro independence parties, the Greens and Alba, did not stand candidates to avoid splitting the independence vote.

In 2015 when the SNP achieved their best ever election result - taking 56 out of Scotland's 59 seats - the party netted 50 per cent of the total votes.

"If Boris Johnson's successor is someone who is even more pro-Brexit that could increase support for independence and the SNP," he said.

"But broadly I would have to say that if someone as divisive as Boris Johnson didn't impact hugely on support for independence, it's hard to say who would," he said.

"I think it's possible for the SNP to get 50 per cent of the votes at a general election. To some extent it would depend on who replaces Boris Johnson.

"Nicola Sturgeon won't have that bogeyman to point to anymore, but she might have a different bogeyman or bogeywoman who may be just as unpopular in Scotland.

"What we do know from polling is that there is a very strong relationship between voters's views on the constitution and what party they support in elections.

"In other words if 50 per cent of voters support independence and the SNP can get the other pro independence parties to stand aside, run a good campaign and get high levels of turn out, there is a chance that they could that. Equally it's a huge risk."

Diffley pointed to a slight change in the SNP's strategy in recent weeks which has seen Ms Sturgeon move towards an attack the Conservatives more widely rather than Mr Johnson being a single target.

Following the resignation on Wednesday of Rishi Sunak as Chancellor and Sajid Javid as health secretary - which ultimately triggered Mr Johnson's downfall, she tweeted: "The whole rotten lot need to go. And needs the permanent alternative of independence."

Scottish Conservative Shadow Constitution Secretary Donald Cameron MSP said: “Irrespective of who is the UK Prime Minister, now is not the time for the SNP to push for another divisive independence referendum that the majority of Scots don’t want.

“The public expect the Scottish Government to focus on their priorities – the global cost-of-living crisis, unacceptable NHS waiting times, plummeting education standards and Scotland’s drug-deaths epidemic – rather than the SNP’s self-serving obsession.”

Kirsten Oswald MP, the SNP's Westminster Deputy leader, said: "While Boris Johnson's resignation is welcome, for Scotland it changes very little – we are still controlled by a Westminster system that saw fit to make him Prime Minister.

"Whoever replaces him, Scotland will still be saddled with a Tory government we didn't vote for imposing an extreme Brexit, austerity cuts and damaging policies against Scotland's will.

"The problems run much deeper than one individual. It's beyond any doubt that the Westminster system is broken and the only way to escape it is to become an independent country, with the full powers needed to regain our place in Europe and build a fair and prosperous future.

"Whoever takes over from Boris Johnson must respect the democratic mandate Scotland has to hold an independence referendum so we can escape Westminster control for good."

Scottish Greens MSP Gillian Mackay said: "There’s no question that Boris Johnson is one of the worst, and least popular, Prime Minister’s in history.

"But, independence is about far more than simply a dislike of one man. Independence is fundamentally about democracy. We can take our future into our own hands, and make decisions that suit our own circumstances.”