IAN Blackford insisted Scotland is "big enough, rich enough and strong enough" to become an independent nation at Prime Minister's Questions as Boris Johnson failed to answer why it couldn't stand on its own two feet.
The SNP Westminster leader spoke about a paper released on Tuesday by the Scottish Government which delved into how European nations similar in size to Scotland have thrived in comparison to the UK in areas such as income equality and social mobility.
And he insisted the research proved Scotland "was being held back by Westminster" and demanded answers from the Prime Minister on why Scotland couldn't be independent.
Johnson's defence included accusing Blackford of trying to create trade barriers within the UK.
Blackford said: "Our First Minister started a national conversation on Scotland’s right to choose an independent future.
"When we look at nations like Iceland, Ireland, Norway and Denmark, it is clear our neighbours are outperforming the UK.
"They deliver greater income equality, lower poverty rates, higher productivity, and business investment. The list goes on and on.
"The evidence is overwhelming, Scotland is being held back by Westminster. All those countries can use the powers of independence to create wealthier, fairer and greener societies. Why not Scotland?"
Johnson did not answer the question and argued there were "other subjects" in the national conversation, including the UK "standing strong together" in sticking up for Ukraine.
He said: "I don’t doubt my right honourable friend’s talents as a conversationalist, but I think there are other things in the national conversation right now and they include what we are doing to come through the aftershocks of Covid with the strongest jobs-led recovery of any European economy.
"I think other subjects are [also] investment in our whole country and in Scotland and the whole of the UK in the tech sector and standing strong together on the international stage and sticking up for the Ukrainians."
Blackford then highlighted how poorly the UK economy was performing with a cost-of-living crisis worse than any other G7 country.
He argued Scotland "cannot afford" to stay "trapped" in a broken Westminster system.
He added: "The Prime Minister can afford to live in his own little Britain but people have to live with the reality of a failing Westminster system.
"A cost of living criss worse in the UK than any other G7 country, an inflation rate double that of France, the second-worst economic growth forecast in the G20 next to only sanctioned Russia, and now the threat of a trade war with our European friends triggered by a law-breaking Prime Minister.
"That is not a vision for the future of Scotland. Our nation is big enough, rich enough and strong enough. Isn’t it the case Scotland can’t afford to stay trapped in the Westminster system? Stop the world, Scotland wants to get on."
Johnson replied: "He talks about a trade war, but what could be more foolish than a project that actually envisages trade barriers within the United Kingdom?"