The UK Government will produce "detailed evidence" of why Scotland is better off in the United Kingdom, Michael Moore has said.
The Scotland Secretary told MPs that the alleged economic benefits of staying in the union would persuade Scots to vote against independence when the referendum is held in autumn 2014.
But the SNP's leader in Westminster Angus Robertson challenged what he called the "anti-independence coalition" to come up with its proposals for further devolution instead.
Answering Scotland questions in the Commons, Mr Moore said: "Leading up to the referendum, the Government will produce detailed evidence and analysis to assess the benefits Scotland gains from being part of the United Kingdom and the contribution Scotland makes to our United Kingdom.
"Over the next 18 months, civil servants will be preparing detailed analysis and evidence that will show the basis of the arguments we need to be involved in as Scotland confronts this great debate.
"Fundamentally, protecting our citizens is one of the most important parts of the role of government; we also want to look at our position in the world and the economic benefits we get as being part of the United Kingdom."
But Mr Robertson said: "You and your Tory and Labour allies in the anti-independence coalition all say they believe the constitutional status quo is not sustainable.
"With only days to go until the formal launch of the 'No' campaign, could you please outline what joint proposals you have for further devolution, what powers will be devolved and when?"
Mr Moore replied: "It's a bit rich for you to come here and ask questions of us. We have just delivered the biggest transfer of financial powers from London to Scotland since the Act of Union.
"Every time we ask you what independence means, your proposals unravel."
Mr Robertson said: "Last time I looked this was Scottish Questions, questions to the Secretary of State and the UK Government.
"So for a second time, given you and your allies say the constitutional status quo is not sustainable, what specific joint proposals do you have for the further devolution of powers?"
Mr Moore said: "I thought you had belatedly, even grudgingly, welcomed the fact the Scotland Act has now put in place the biggest transfer of financial powers on borrowing, the Scottish rate of income tax, the transfer of stamp duty land tax north of the border.
"Can I say the debate we all need to get on with is the one about independence. That's why the UK Government is absolutely committed to ensuring the evidence and the analysis, working with experts, academics and other outside bodies, to ensure we are equipped for this great debate across the country."
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