Scotland “is shackled to a sinking ship” as the UK heads towards a hard Brexit, the SNP has said.
Ian Blackford accused the UK Government of a “shameful” lack of Brexit preparation and warned crashing out of the European Union could be an “economic catastrophe”.
He also said Chancellor Philip Hammond “deserves a red card”, as he poked fun at Scottish Tory MP Douglas Ross.
Mr Hammond said the Scottish economy was growing slower than the rest of the UK under the SNP, adding it was “about keeping afloat” for his colleagues north of the border.
Mr Blackford, the party’s leader at Westminster, said: “The progress of this Government in readying for Brexit has been nothing short of shameful.
“The UK Government’s own analysis tells us that under all scenarios, Scotland would suffer a relatively greater loss in economic output than the United Kingdom as a whole.
“A no deal scenario would be significantly devastating, threatening to reduce growth by a massive 9% over 15 years.
“Make no mistake that a hard Brexit is going to hit the pockets of families, is going to lead to a loss in tax revenue expectations. It’s therefore going to affect spending on public services, and yet the Chancellor is silent on the risks to our economy.
“Risks to our economy, when the stresses and strains of a near-decade of austerity is hurting. The fact is, Scotland is shackled to a sinking ship.”
In his response to the Spring Statement, Mr Blackford raised cuts to Scotland’s block grant from the UK Government and the “vindictive” measure to charge VAT on Scottish police and fire services, which has since been ended.
Mr Blackford said the SNP would continue to campaign for single market and customs union membership “to prevent the economic catastrophe of an extreme Tory Brexit”.
He added: “I have to say that was much ado about nothing, and the real tragedy is that we’re 10 years on from the financial crisis, and austerity is still with us and there was a lack of hope given to the people of the United Kingdom from this statement today.”
Mr Hammond said: “A matter of rather more immediate urgency for the people of Scotland will be how their economy will withstand the highest rates of taxation in the United Kingdom.
“An economy that under the SNP government is already growing more slowly than the economy of the United Kingdom.
“I don’t know about sinking ship. It’s about keeping afloat, I’d suggest to him.”
Mr Hammond went on to say that Theresa May “is working tirelessly to deliver a Brexit that will secure British jobs, British businesses and British prosperity”.
The Chancellor said: “We would be aided in that enterprise if he and his government would work closely with us to deliver an outcome that’s good for the whole of the United Kingdom.”
Mr Blackford also poked fun at Scottish Tory Mr Ross, with the Moray MP having been an assistant referee at the weekend in the Old Firm match between Rangers and Celtic.
“At the weekend we saw (Mr Ross) in his other job as a linesman at the Glasgow Celtic vs Rangers football match, waving a flag enthusiastically calling for a red card,” said Mr Blackford.
“If anybody deserves a red card today, it’s the Chancellor of the Exchequer.”
Tory MPs shouted at Mr Blackford that it should be him who received the red card.