The Liberal Democrat leader claimed the SNP leader refused to accept the result of last year’s public vote in Scotland.
Ms Sturgeon has not ruled out pushing for another vote but has placed a “triple lock” on the issue, saying it would require a change in public opinion, the election of a party proposing independence and then another referendum.
Mr Clegg said: “It is of huge significance that despite their protestations that they have got no plans to keep constantly asking everybody the same question until they get an answer they want, actually that is precisely what they intend to do.
“I think that would have a paralysing effect on the Scottish economy and would have a paralysing effect on the UK economy as a whole if we’re constantly trying to guess every few years whether the SNP are going to get their way.
“They just don’t seem to be able to accept the answer they received at the ballot box.
“There is almost a sort of Maoist tendency which says that the people must be wrong according to the SNP and that they must be forced to ask themselves the question over and over and over again until they give the answer which is satisfactory to Alex Salmond and Nicola Sturgeon.”
Speaking on his campaign battle bus, he added: “It is a bit like that Japanese soldier who emerged from the jungle after 30 years and he thought the Second World War was still on. I sometimes think the SNP’s a bit like that.”
Mr Clegg faces the potential loss of key allies in Scotland including Treasury Chief Secretary Danny Alexander as a result of the SNP surge.
Asked if the Union was still in jeopardy despite the result of last year’s referendum, Mr Clegg said: “Of course there is a risk that the Union is pulled apart by a party, the SNP, whose sole purpose in life is to do just that.
“That’s why I think their arguments do need to be challenged and why I’m pleased to see Nicola Sturgeon’s comments are being challenged a bit more.”
SNP Westminster leader Angus Robertson said: “This a very silly intervention from Nick Clegg, and is not be sort of language to use about the very people intending to vote SNP next month.
“The reality is that a strong group of SNP MPs in the House of Commons will stand up for Scotland and help deliver progressive politics across the UK.
“That will be positive and refreshing - in stark contrast to the cruel Tory cuts that the Lib Dems have been cheerleaders for these last five years.”
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