Chancellor George Osborne's expected to rule out the possibility of an independent Scotland keeping the pound when he makes a speech in Edinburgh later.
Nationalists say the UK government is bluffing and that a currency union is the best option.
More top news
Alex Salmond announced he will stand down as Scotland's First Minister and SNP leader after voters rejected independence in the referendum.
The SNP supporters who voted against independence, and nine more interesting snippets from Lord Ashcroft's unofficial "exit poll".
The Scottish independence referendum was threatening to turn into a huge boost for separatist movements in many countries in Europe.