UPDATE: Royal Babies Are 'Above Politics,' Says Alistair Darling As Duchess Of Cambridge's Second Pregnancy Is Confirmed
Supporters of the union are mounting a frantic fightback after a shock poll suggested the United Kingdom could be consigned to history in 10 days' time.
David Cameron, who spent the weekend with the Queen at Balmoral, will this week attempt to convince sceptics that Scotland will get significantly more autonomy even if independence is rejected.
The push - which has been dismissed as "panic" by the pro-independence camp - came after the contest was set on fire by YouGov research for the Sunday Times.
It suggested Yes had taken the lead for the first time, with 51% support compared to 49% for No.
The two-point advantage, which excludes those who do not know or do not propose to cast a ballot, is within the margin of error and suggests the result is too close to call.
It marks a stunning turnaround for Alex Salmond's campaign, which was trailing by 22 points just a month ago.
Another Panelbase survey put the pro-union side slightly ahead No at 52%, with 48% favouring independence.
Writing in today's Daily Telegraph, Tory Mayor of London Boris Johnson made an emotional appeal to keep the UK together, warning Scottish independence would be "an utter catastrophe for this country" and that he hopes “we will wake from this sleepwalk to tragedy”.
"We will all have lost a way of thinking about ourselves, a way of explaining ourselves to the world," he wrote.
"We are on the verge of trashing our global name and brand in an act of self-mutilation that will leave our international rivals stunned, gleeful and discreetly scornful."
Chancellor George Osborne yesterday promised a "plan of action to give more powers to Scotland" would be unveiled in the next few days, detailing the timetable and process of any further devolution.
Meanwhile, Labour is deploying some of its biggest beasts to try to halt the apparent nationalist surge - with Ed Miliband also stressing that extra powers will start being devolved "right after" a No vote.
Over the coming days Mr Miliband is expected to share a platform with his predecessor as Labour leader, Gordon Brown, for the first time since the 2010 general election campaign.
Shadow chancellor Ed Balls, who will take to the stump in Aberdeen later, has used an article in the Daily Record to entreat Scots not to use their votes as a "protest" against "callous" Tory policies emanating from Westminster.
Former Nato Secretary General Lord Robertson - who has already claimed Scottish independence could have a ''cataclysmic'' impact on the world - will be campaigning with former Scottish secretary Jim Murphy.
The Chief Secretary to the Treasury Danny Alexander will also be urging Scots to vote No as he visits the Weir Group, whose chief executive has already claimed leaving the UK could bring ''substantial risks'' to the economy.
However, jubilant nationalists have insisted public opinion is moving in their direction.
Scottish Alex Salmond dismissed the devolution move as a "bribe" from Westminster politicians.
Speaking on BBC's Sunday Politics Scotland the First Minister said: "Are we expected to believe, after hundreds of thousands have already voted, that there's a radical new deal?
"This is a panicky measure made because the Yes side is winning on the ground."
He added: "They're trying to bribe us, but it won't work as they have no credibility left."
His SNP deputy Nicola Sturgeon, addressing undecided women voters in Glasgow, said: "I think the No campaign is missing the fact that this campaign in Scotland has moved beyond any place where people can have the wool pulled over their eyes."
Leanne Wood, the leader of the Plaid Cymru Welsh nationalists will team up with Ms Sturgeon to campaign for a Yes vote.
The Party of Wales has backed the SNP's warning that ''privatisation'' of the NHS in England could lead to a cut in health funding for the devolved regions - a claim dismissed as ''scaremongering'' by the unionist parties.