SNP MSP: It's 'too easy' for politicians to blame Westminster and Brexit

But instead, it is "far easier" for politicians to simply blame Brexit and the UK Government, she said.

READ MORE: Scotland’s economy 'lags other small countries'

Ms Forbes made the comments during an event by the think tank Reform Scotland, which was discussing a new report by economics advisor David Skilling.

Mr Skilling found Scotland’s economy has “lagged behind” that of other advanced small nations, with a slowdown in the oil and gas sector hitting GDP growth and the UK acting as a “drag on performance”.

He said an independent Scotland would have to move quickly to cut its deficit, while also warning it would need to “think hard” about the impact of any tax hikes.

Ms Forbes said Scotland’s potential outstrips its performance as a country, and called for cross-party agreement on pushing the economy forward.

But she said “easy headlines” and impatience often meant the potential to reach across partisan lines was lost.

She told the event: “This is where you can tell I’m not currently acting as my party’s spokesperson. It goes back into the first point of the tendency we have to blame and find responsibility.

“It’s so easy. Sometimes I think it would be far easier to be in the opposition, because it’s so much easier to blame.

“It’s far easier for me – and I do it all the time – to stand up and blame Brexit or to blame Westminster or to blame somebody else.

“But the truth of the matter is, as the report states, at times of crisis and when we do as a country have exposure to the poor performance of the United Kingdom and our current direction of travel, which is to increase friction when it comes to our borders.

READ MORE: Trust between Holyrood and Westminster at 'lowest ebb in a decade'

“I don’t think many people are at odds on the fact that it is a time of crisis. At a time of crisis, we need to use it as an opportunity to prepare. And that’s difficult. It’s immensely difficult.”

Yesterday, Mr Mackay reiterated calls for Holyrood to take control of immigration powers in order to boost economic growth.

The Finance Secretary said the UK Government's target of reducing migration to the tens of thousands was "unhelpful" to Scotland, which has an ageing population.

In his report, Mr Skilling looked at the performance of countries including Ireland, New Zealand, Norway, Sweden, Finland, Hong Kong and Switzerland, where GDP per capita was measured at £60,000 – more than double the Scottish figure.

He said there was “no single specific policy model” for a successful small country, but insisted he was generally optimistic about their prospects in the global economy.

However, he argued the intensity of competition was increasing, while the “unusually supportive environment” for small, open economies after the Second World War was becoming more challenging under the influence of Donald Trump and China.

Mr Skilling also warned an independent Scotland would need to “think hard” about issues such as income tax.

He said: “You need to think hard about the competitive impact in terms of how attractive Scotland is to firms and to people.”

He added: “There’s no magic tax rate above which you're in trouble and below which you’re fine, but I do think it’s one of the elements that plays to competitiveness.

“So if you’re raising the tax rate – obviously it increases the cost structure, [and] you need to have a degree of confidence that you have other things going on that are going to make that feasible and sustainable.”

READ MORE: Scotland’s economy 'lags other small countries'

Changes introduced this year mean more than one million Scots pay higher income tax than those earning the same elsewhere in the UK.

Mr Skilling’s analysis comes after the SNP’s new independence blueprint recommended keeping the pound for ten years while limiting public spending to reduce Scotland’s deficit.

His report was written for Reform Scotland and part-funded by the Scottish Policy Foundation.