The Scottish government's ambition to maintain influence over the Bank of England after independence has been scoffed at by a House of Lords committee as an "entirely fanciful" notion.
Peers including a former chancellor made the claims in a report on the economic implications of Scottish independence for the UK.
The report takes a broad look at issues including currency, banking, financial regulation, assets and liabilities.
While raising specific concerns on the future impact, members of the Select Committee on Economic Affairs also criticised ministers on both sides of the border for failing to be open with the electorate.
Focusing on more technical economics, the report said currency is "perhaps the most important economic decision" and urged both governments to put forward details in good time for the public to make informed decisions.
Scottish finance secretary John Swinney favours keeping sterling in monetary union with the rest of the UK, using the Bank of England as lender of last resort.
North Sea oil is expected to continue to raise money for Scotland's coffers
The peers insist it would be "unacceptable" for the monetary policy committee of the bank to have members representing the interests of a separate country. It also raised concerns about the role of lender of last resort.
"For the Bank of England to provide central bank services to substantial financial institutions operating in an independent Scotland and regulated by a body reporting to an independent Scottish government implies that the bank would accept risks over which it had little control, which seems implausible," it states.
The Lords summed up: "Arrangements should be clear before the referendum. But the proposal for the Scottish government to exert some influence over the Bank of England, let alone the rest of the UK exchequer, is devoid of precedent and entirely fanciful."
Committee chairman Lord MacGregor said: "We hope that our report provides a road map for all the key issues - single market, division of assets and liabilities, North Sea oil, currency, taxation and debt, international issues including membership of the EU and defence.
"Many of these issues could not be clarified - if there is a Yes vote - until after negotiations following such a vote. So we recommend in particular that the Scottish and British governments should indicate the red lines of their negotiating stance on them before the referendum so that voters can make an informed choice.
"We do not take a position on whether voters should vote yes or no on September 18 2014 but they deserve to cast their vote based on a proper understanding of the possible economic impact. At present they do not have the information to do so."
The report contains recommendations to both governments on specific themes.
On the single market, the peers said any future governments should try to preserve the single UK market and retain sterling.
Physical assets, such as oil, would have to be divided on a geographic basis, as proposed by the SNP. Liabilities would be split by population share.
John Swinney described the House of Lords as 'out of touch'
The volatility of oil revenue and its impact on a future Scottish Treasury has been a key feature in the debate. The peers highlighted offshore decommissioning costs of £30 billion over 30 years which could hit Scottish finances. Despite those concerns, the report adds: "It remains the case that the Scottish economy would be likely to gain from North Sea oil revenues.
"The scale of that gain is much more uncertain as is how long it will last. Oil alone will not ensure that an independent Scotland is a prosperous Scotland."
An independent Scotland would also face the prospect of adding future liabilities such as pensions to the balance sheet. Assuming a proportionate £93 billion in public-sector debt and a share of North Sea oil, the ratio of debt to GDP would be about 62%, the report calculates.
Added to future liabilities, the figure would become 123% of GDP, it adds.
It is up to the Scottish government to explain how it would take over its share, the peers said.
The committee also looked at defence issues, limited to economic impact, and criticised a refusal by UK ministers to answer questions.
"The government should take every chance to make things clearer," the report states.
"Its acknowledgement of time and cost implications if an independent Scotland demanded the withdrawal of the UK (nuclear) deterrent is a step in the right direction. But there is a long way to go."
A lack of defence policy for an independent Scotland means there is "not enough" information for voters to make an informed decision, the report adds.
Finance secretary John Swinney said: "It will be no surprise to people across Scotland that out of touch unelected Lords think Scotland is too small and too poor.
"Westminster has been peddling this nonsense for decades and even the No campaign no longer believe it.
"All the evidence, including in this report, shows Scotland is in a far stronger financial position than the UK as a whole.
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"We are firmly committed to ensuring the people of Scotland have all the information they need on the opportunities of independence to take the positive step forward with a Yes vote in 2014, which amongst other things would bring an end to unelected Lords talking Scotland down."
Responding to claims on currency and defence, Mr Swinney added: "Retaining sterling as Scotland's currency within a formal monetary union is a proposal endorsed by the leading and Nobel prize winning impartial economists of the Fiscal Commission who advise governments and economic institutions around the world and who are very clear that this is in the UK's best interests as well as Scotland's.
"The report's claims on defence jobs are simply ridiculous. Their claim that 25,000 jobs could go is undermined by evidence from the UK government in the same report that the number of MoD personnel is 15,000 and the defence industry accounts for 12,000 at most.
"The only area where the Lords have hit the right note is in their view that the UK government is failing to take the prospect of independence for Scotland seriously."
Scottish Conservative chief whip John Lamont said: "This thorough and independent report lays out in stark detail the reality of Scotland separating from the rest of the United Kingdom.
"It rightly points out that Scotland currently enjoys the insurance policy of being part of the UK when things go wrong, such as the banking crisis.
"The report exposes the fact the SNP have yet to fully answer big questions on Scotland's share of the debt, currency, oil revenues or defence.
"It shows that under independence, the country would have no established credit history, yet would be taking on a debt equivalent to £35,000 for every person in Scotland.
"Furthermore, it says that keeping sterling would mean handing over control of Scotland's monetary policy to a foreign country, affecting people's mortgages and bank loans.
"Alex Salmond's answer to any criticism of his spending plans is that oil revenues will pay for everything but the report exposes the dangerous folly of basing an economy on something as volatile as oil.
"Even on defence, which is the first responsibility of any nation, he has no answers."
Chief secretary to the Treasury Danny Alexander said: "This independent report raises many questions that must be addressed by the Scottish government before the independence referendum.
"We have been clear we will not 'pre-negotiate' the terms of independence before people in Scotland have had their say in the referendum. To do so would require the government to act on behalf of only part of the UK."