Scottish independence would be a "disruptive shock" for the nation on the same scale as the oil crisis of the 1970s or the financial crisis that sparked the global recession, a leading Labour MP said.
Jim Murphy also likened the impact of Scotland leaving the UK to the decline of heavy industry in the 1980s under Margaret Thatcher's Tory government.
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He went on to warn that a Yes vote in September's independence referendum would hit the poorest "people with least influence" the hardest, saying such families could be £1,000 a year worse off as a result.
Mr Murphy, the shadow international development secretary, said: "In my lifetime there have been three enormous, disruptive shocks - the oil crisis of the 1970s, the industrial crisis and shock of Thatcher in the 1980s, and the financial shock of 2008.
"Scotland is now faced with the potential for a fourth shock of that nature - Scottish independence."
He told the Scottish Labour conference in Perth: "We should make no mistake, this would be a disruptive shock. That's not negative to say that, in fact it is the very disruption of leaving the United Kingdom that makes it so seductive to Nationalists.
"But the truth is in all these disruptive shocks we find is that those people who pay most are those who can least afford it, the people furthest from power, the people with least influence, those are the people who pay the longest when it comes to any disruptive shock.
"That's why research shows that those families will be £1,000 worse off as a consequence of independence."
Mr Murphy said the UK had a Tory Government with "no answer for the poor", while he said the SNP's proposals for independence were "no solution to the complexity of today's world".
He hit out at Alex Salmond's party and said: "How can you in any way have any sense of radicalism if your blind desire is you will spend less than Labour and you will cut taxes more than the Tories, there's no sense of radicalism in that.
"It's not radical to be so focused on making history that you turn your back on the families trying to make ends meet, that 's not radicalism of any sort, it's a Nationalist form of Toryism."