A shock Scottish independence poll that put the Yes campaign in the lead is a "wake up call" to those fighting to keep the UK together, its leader has said.
YouGov research for the Sunday Times put the pro-independence campaign ahead by 51% to 49%, after weeks of momentum and growing support for independence campaigners - which has stunned those who thought next week's referendum was "a forgone conclusion" in Alistair Darling's words.
The leader of the Better Together campaign said the poll was "a wake-up call to anyone who thought the referendum result was a foregone conclusion".
"The polls may conflict but the message I take from them is clear: If you want Scotland to remain part of the UK family you have to vote for it on September 18. Separation is forever," he added.
"These polls can and must now serve as a wake-up call to anyone who thought the referendum result was a foregone conclusion."
After the poll put the Yes campaign in the lead for the first time, Chancellor George Osborne said the final touches were being put to proposals for "much greater" fiscal autonomy and tax-raising abilities.
Speaking on the BBC's Andrew Marr show this morning, Mr Osborne denied that dire warnings about the dangers of splitting up had backfired.
He said: "This country faces a very, very big choice. Scotland faces a very big choice.
"If people were in any doubt that they can stay at home, that they don't need to go out to the polls and vote No to avoid separation, they won't be in that doubt today.
"They should also be in no doubt about the consequences of this decision - one of which is that Scotland will not be sharing the pound as an independent country with the rest of the UK if the separatists win the vote."
Mr Osborne said sharing the currency after independence would be equivalent to a couple divorcing but retaining the same bank account.
"No ifs, no buts. We will not share the pound if Scotland separates from the rest of the UK," he said.
The Chancellor said it was "clear" Scotland wanted more autonomy and the Tories, Labour and the Liberal Democrats had agreed to "deliver" on that.
He added: "You will see in the next few days a plan of action to give more powers to Scotland. More tax powers, more spending powers, more plans for powers over the welfare state.
"That will be put into effect - the timetable for delivering that will be put into effect the moment there is a No vote in the referendum.
"The clock will be ticking for delivering those powers, and then Scotland will have the best of both worlds.
"They will both avoid the risks of separation but have more control over their own destiny, which is where I think many Scots want to be."
The reforms would include "much greater" fiscal autonomy and control over tax rates as well as more powers over welfare rates.
Mr Osborne also played down speculation that Prime Minister David Cameron could be forced to resign in the event of a Yes vote.
"This is not about the future of the British Government in Westminster. This is not about the future of myself or David Cameron or anyone else," he said.
The poll is the latest evidence of a dramatic surge for the Yes Scotland campaign, which has seen it overturn a 22-point deficit in just a month.
Support for independence is said to have soared four points in a week while No dropped by the same number.
The headline figures exclude those who would not vote or are undecided. With those groups included, independence was backed by 47% and staying in the UK 45%.
The two-point gap is within the margin of error for such polls, meaning the contest, which climaxes on September 18, is effectively too close to call.
A particularly alarming aspect for unionists is the suggestion that 35% of Labour voters now back independence, compared to 18% a month ago.
Scotland's Deputy First Minister Nicola Sturgeon described the findings as "exceptionally positive" but added that the Yes campaign "still has a lot of work to do to win".
Rumours about the latest YouGov findings had been swirling for days, with signs of recriminations already emerging among the No camp.
Writing in The Sunday Mirror, former prime minister Gordon Brown acknowledged that the referendum battle was proving tougher than some had expected - and laid the blame squarely with the Tories.
"Why has it been difficult to win Scottish votes in support of this principle of sharing that most Scots hold dear?" the Labour MP for Kirkcaldy and Cowdenbeath wrote.
"Many are angry that the bedroom tax was imposed upon Scots against their will while at the same time the very wealthy received tax cuts.
"The SNP also claim that the ramifications of any Tory privatisation of the NHS in England will cut budgets in Scotland.
"But English and Welsh people have already given an answer to the SNP claims.
"The answer is that 90% of English people want to keep the NHS public and retain it free at the point of need.
"And the vast majority across the whole UK dislike the bedroom tax and would even consider more taxes to make our NHS better."
A second poll, carried out by Panelbase for Yes Scotland, found that No is leading 52% to 48% when undecided voters are excluded.
The Panelbase poll also found that 47% of women support independence, which Yes Scotland say is a 13-point increase in six months.