Scottish ministers would have a mandate to begin independence negotiations with the UK Government if the SNP win a majority of votes in Scotland at the next General Election, John Swinney has said.

The Deputy First Minister made the comments during an interview with the BBC this morning after he was asked what course of action would be taken if the Supreme Court rules against Nicola Sturgeon’s bid to hold a legal referendum on 19 October 2023.

He initially agreed with the suggestion a majority of seats for the SNP would deliver a mandate, but later clarified his comments. 

Mr Swinney said on Twitter he had not heard the question fully and that a win in a general election being used as a defacto referendum would be determined by which party won the most votes.

"When BBCGaryR asked me about a "majority of seats" this morning on #bbcgms, I only picked up on "majority". Referenda, including de facto referenda at a UK General Election, are won with a majority of votes. Nothing else," he tweeted.

Setting out her route map to a new independence vote to MSPs at Holyrood yesterday, the First Minister revealed that she has written to Prime Minister Boris Johnson seeking a Section 30 order which would transfer powers from Westminster to Holyrood to hold a legally binding vote.

However, with the PM refusing to agree to a new vote, she plans to hold a new referendum in autumn next year using Holyrood legislation should he continue to reject her request.

Amid legal uncertainty over whether the Scottish Parliament has sufficient powers to hold a lawful referendum she has asked the Lord Advocate to refer her plans to the Supreme Court.

She said that if the court rules her proposals are not lawful she would not hold the vote next year and instead would consider the next Westminster election as a “de facto” vote on independence by campaigning on the single issue 'Should Scotland be an independent country'.

On Tuesday, after the SNP leader set out her route map to a second referendum, senior sources told journalists that more than 50% of votes cast would have to be for pro-Yes parties for the result to be considered an endorsement of independence.

But speaking on Wednesday morning, Swinney initially agreed that a majority of SNP MPs – a minimum of 30 out of 59 – would be required. The SNP won 56 out of 59 seats in Scotland in 2015, and currently have 45 following the resignation from the party at the weekend of Patrick Grady. In 2015 and 2019 it won 50% and 37% respectively of the total votes cast.

In the event that the SNP win that election, the Covid Recovery Secretary said: “We will very clearly have the expression of the will of the people of Scotland. And if we live in a democracy, if we live in a democracy where the views and opinions of the people of Scotland are recognised and responded to by the UK Government, then the process of Scotland becoming an independent country should take effect.

“But that will, as the First Minister said yesterday, only come about by a negotiation and legislative process that involves the UK Government and the Scottish Parliament in that process.”

Asked directly if a majority of SNP MPs at the next General Election would represent a mandate to begin independence negotiations with Westminster, the deputy FM replied: “That is correct, yes.”

However, he later clarified his agreement saying he had misheard the question. 

Ms Sturgeon has also suggested that a majority of votes would be required, as opposed to a majority of seats.

Asked about the possibility of a General Election being used as a “defacto” referendum, she told BBC Breakfast: “I’ll set out this in more detail should we be in this situation, which I hope we won’t be in because I hope we'll be able to have a lawful referendum.

“But the first issue of principle is that – and I've always said this – Scotland can only become independent if a majority of people vote for that proposition. And secondly, when a majority of people do vote for that proposition, as a matter of practical reality, and this will be true after a referendum, we have to negotiate the implementation of that with the UK Government.”

She added: “Actually it's the UK Government that should be getting pinned on the what ifs here. What I'm trying to do is respect democracy and the rule of law and to work away to deliver the mandate in the Scottish Parliament for a lawful referendum. And if that is blocked every time then what does that say about UK democracy? What does it say about the nature of the UK – certainly not a voluntary union of equals.”

The date of the next general election has not yet been announced with the lats vote taking place on 12 December 2019.

Under existing rules the maximum term of a UK Parliament is five years from the day on which it first met.

The current one first met on Tuesday 17 December 2019 and will automatically dissolve on Tuesday 17 December 2024, unless it has been dissolved sooner by the Queen.

Polling Day would be expected to take place 25 days later.

Pamela Nash, chief executive of Scotland in Union, seized on the apparent differences of views between the First Minister and her Deputy on what would amount to a win in terms of a mandate for independence at a general election.

Before Mr Swinney clarified his statement, she said: “It took less than 24 hours for Nicola Sturgeon’s plan to plunge into confusion – although she probably wasn’t expecting her top lieutenant to be responsible.

“John Swinney might claim he misheard, but it’s clear that the SNP is making it up as it goes along in a desperate attempt to placate ultra-nationalists.

“The SNP has given up all pretence of governing.

“The people of Scotland deserve a government that focuses on investing in public services and bringing communities together, which is only possible by remaining part of the UK.”

Scottish Labour Constitution spokeswoman Sarah Boyack also said: “This desperate claim from John Swinney exposes the SNP for what they are – obsessive nationalists who are hell-bent on gaming the electorate to suit their ends.

“It is deeply embarrassing for Nicola Sturgeon to be so publicly contradicted on the barometer for independence by her own deputy.

“This is just a tired party, trying to deflect attention from their failures in government.

“The Nicola Sturgeon of the pandemic is gone. This is the return of the divisive Nicola Sturgeon who wants to drag our country back to the arguments of the past.

“This is not the time to pit Scot against Scot – we must be focused on tackling the cost of living crisis and re-building Scotland for the future.”