Bill Etheridge blasted former MSP Andrew Wilson, the chairman of the SNP’s Growth Commission, after he made the case for a second Scottish independence referendum on BBC Radio 4.
He said Mr Wilson’s comments were "like reliving the nonsense economic predictions of the Remain campaign during the EU referendum”.
The SNP member has told the radio station “fraught” economic circumstances justified another vote.
“It’s true the economic circumstances are fraught at present. The world sea is very stormy, you see the energy sector has had troubles and the fiscal inheritance we would have from the rest of the UK is a very difficult one,” said Mr Wilson.
Bill Etheridge blasted Niciola Sturgeon's party over calls for another independence referendum
I am well aware there are other similar sized countries that have thrived but they didn't have Nicola Sturgeon and Jean-Claude Juncker at the helm
“All of the above however would be a reason to change the way we’re operating rather than to stay stuck to a deckchair on the Titanic and I think we are able to put an exposition into the debate which people will be able to respect.
“They might not agree with it but there are plenty of precedents that we’re looking to from around the world, small countries which have put governments in place, put programmes in place that can ensure that the economy grows and welfare of people increase.”
Mr Etheridge took aim at Nicola Sturgeon in his response to the comments.
He told Express.co.uk: "I am well aware there are other similar sized countries that have thrived but they didn't have Nicola Sturgeon and Jean-Claude Juncker at the helm.
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Mr Etheridge took aim at the SNP leader after Andrew Wilson likened the UK to the Titanic
"A country of any size can thrive if it has the right economic policies based on free markets and deregulation rather than taking money away from hard working people and wasting it on foreign aid, quangos and trade policies which push up prices.
"As for saying the UK economy is bad, the UK economy has defied Project Fear and I believe if we have the right blend of free trade, deregulation and lower taxes, everyone in this country can be better off."
The Brexit campaigner also responded to Mr Wilson’s calls for “mutually beneficial” trading with the UK and the EU.
He said it appeared to indicate the SNP did not grasp "the huge benefits of free trade which politicians get in the way of".
Mr Etheridge added: ”Free trade makes the world better off, through a better allocation of scarce resources to greater competition, helping the developing world and ending the control that huge multinationals and cartels have over government policy."