Chancellor George Osborne has challenged the Scottish Government to answer three questions about the economy of an independent Scotland, claiming the SNP administration is in "denial" with just weeks to go to the referendum vote.
Mr Osborne said questions on currency, the deficit and the impact of falling oil and gas revenues on the Scottish economy remain unanswered.
First Minister Alex Salmond's "passion" for independence is blinding him to the risks posed to Scotland, the Chancellor said.
He highlighted the decision of the Office for Budget Responsibility (OBR) to revise down its North Sea oil forecasts last week, saying Scottish Government plans rested on a "volatile and declining" source of revenue.
SNP proposals to boost spending and cut taxes do not add up in a country that would face a deficit around twice the size of the UK after independence, Mr Osborne said.
He also repeated calls for Mr Salmond to clarify plans for the currency of an independent Scotland given the opposition of UK parties to a currency union.
Writing in The Daily Telegraph newspaper, Mr Osborne said: " With just under 10 weeks till the referendum the Scottish Government still can't answer basic economic questions about its plan for a separate Scotland.
"These are questions that shape all our lives - they dictate our mortgage rates and tax bills; the quality of our schools and hospitals; the safety of our jobs and opportunities for our children. Our economic security hangs on the answers.
"Alex Salmond is proposing that Scotland goes it alone. But he can't tell people how public services will be funded, how Scotland will pay its way in the world, or even what currency people will be paid in. In his passion for independence, he is blinded to the risks to Scotland."
A spokeswoman for Finance Secretary John Swinney said: "It is no surprise the UK Government talks down oil revenues when even they admit that their policies have damaged the North Sea and discouraged investment.
"As Professor Donald MacKay has set out, the OBR's forecasts rest on estimates of future production which are well below that used by the industry, by leading experts and by the UK Government themselves.
"An independent Scotland would be one of the wealthiest countries in the OECD, and as recent figures show, we would have been wealthier per head than France, Japan or the rest of the UK. And as George Osborne knows, a UK Government minister has already accepted that a currency union will be agreed because it is in the best interests of the rest of the UK's economy as well as Scotland.
"An independent Scotland would start life with lower debt to GDP ratio than the rest of the UK and the ability to invest in creating a more prosperous Scotland at the same time as reducing the deficit instead of embarking on a reckless and dangerous £25 billion of cuts proposed by George Osborne and his No campaign allies."