THE SNP MSP who sparked a furore by claiming that a post-independence trade border with England would “create jobs” has been challenged to prove it.

As Nicola Sturgeon today tried to defuse the growing row, Scottish Tory leader Douglas Ross said Emma Harper should back up her controversial claim.

He said: “The SNP have to substantiate those claims from one of their current MSPs and a candidate in this election.”

Ms Harper, who is the SNP candidate in Tory-held Gallloway & West Dumfries, was accused of spouting “half-witted nonsense” after an interview with ITV Border yesterday.

READ MORE: SNP MSP claims border with England would 'create jobs'

After criticising the post-Brexit border down the Irish Sea, she was asked: “So why add another one here?”

The South Scotland MSP replied: “If a border will work, we can show that a border will work, there are issues that have been brought to my attention that show that jobs can be created if a border is created. And again, we want the softest of borders.”

Under the SNP's plans, an independent Scotland would rejoin the EU, meaning the border with England would also be an external EU border, and so trade across it would be tightly regulated.

LSE academics recently suggested it could add 15 to 30 per cent to trade costs.

The First Minister was today dragged into the controversy, telling Radio Clyde that “nobody in the SNP wants to see a border between Scotland and England”.

She said: “This is only being talked about because the UK Government has decided to leave the EU and rip Scotland out of the EU.

“I want Scotland to trade freely across the UK and to trade freely within the world’s biggest single market, which is the European Single Market.

“It is the Tories that are about borders, it’s the SNP (that) are about Scotland being an independent country but then operating economically and socially on the basis of equality.”

READ MORE: Sturgeon insists SNP 'don't want Scotland-England hard border'

Speaking to the media about the row later, Ms Ross accused Ms Sturgeon of trying to duck the issue.

He said Ms Harper’s comments were “incredible” given she represented South Scotland and was standing in a Borders seat. 

He said: “I think people in Dumfries & Galloway will view her comments very poorly.

“They probably shed a light on the thinking within the SNP. It’s always about independence, separating from the rest of the United Kingdom.

“But to some how claim that there are benefits of a border between Scotland the rest of the UK is completely false and fanciful.

“However I did note that she said issues had been brought to her attention that show jobs can be created. 

“So there’s a genuine question there to an SNP representative - show us that information. 

“Surely you weren’t misleading the public and the media by telling people that issues had been brought to her attention that would show you would create jobs if you create a border?

“I think now the SNP have to substantiate those claims from one of their current MSPs and a candidate in this election.”

The SNP was asked for the information to which Ms Harper referred. 

An SNP spokesperson said: "Independence is about getting rid of governments that Scotland doesn't vote for - not putting up barriers.

"The Tories are the party that put a border in the Irish Sea, and between Scotland and the European Single Market, which is seven times the size of the UK. 

"It's not the SNP that is proposing borders -and as an independent member of the EU, unlike now, people would benefit from freedom of movement both with the rest of the UK and the EU. 

"It is Boris Johnson's disastrous hard Brexit that will hold back recovery and as Emma Harper said we want trade between Scotland and the rest of the UK to be as seamless as possible."