The Don't Knows hold key to separation: Final series of polls suggest future of the UK hangs in the balance

• More than 150,000 still undecided on most prolific vote in country's history
• Final polls show four per cent of electorate have still to make up their mind 
• The biggest survey puts No in lead with 52 per cent of vote 
• Comes as both sides of debate launched last-ditch bids to sway undecideds
• Rousing speeches from both campaigns heralded final day of campaigning
• Alex Salmond promised roaring crowds 'the opportunity of a lifetime' 
• Gordon Brown implored No voters to 'Have confidence in saying No' 
• More than 90 per cent of Scottish voters expected to turn out today 

• A final series of opinion polls last night suggested the future of the UK hangs in the balance – but Alex Salmond will still have to win over huge numbers of voters who remain undecided to clinch victory.

  Pollsters gave the No camp a lead of between two and six points.

  The biggest survey, by YouGov for the Sun and the Times, put No on 52 and Yes on 48. 

  Crucially, however, it suggested that just four per cent have yet to make up their minds - well down on recent figures.

  

  With just hours until the historic referendum, a new poll has placed the No campaign in the lead with 51 per cent

  If correct, almost all the undecideds – some 170,00 or so voters – would now have to break for Yes for independence to get the go ahead.

  A Survation poll for the Daily Record, excluding the nine per cent who said they did not know how they would vote, put Yes on 47 per cent and No on 53 per cent. Last night’s polls confirmed that women remain more resistant to independence than men.

  Incredibly, the YouGov poll found that Ed Miliband is now less trusted than David Cameron in Scotland, traditionally a Labour heartland, on 25 per cent against 26 per cent for the Prime Minister.

  The tightest referendum poll left the No camp with just a two-point lead. The Ipsos MORI survey for STV put support for Yes on 49 per cent against 51 per cent for No, once undecided voters are excluded.  

  Alex Salmond promised voters 'the opportunity of a lifetime' in his final speech given in Perth last night 

  

  Gordon Brown was hailed as having given the speech of the No campaign after imploring voters in Glasgow to 'have confidence' and say No

  

  Appearing on the Andrew Marr Show earlier this week, Alistair Darling conceded the race was close with many voters still undecided while SNP leader Salmond said he was taking 'a premature victory lap' 

  

  Wednesday night saw the final and most ferocious night of campaigning with much of Scotland lit up with signs in favour of or against independence. A No Thanks logo lights up Edinburgh castle

  

  A giant Yes sign, created by campaign group The Hills Have Ayes, appeared on the Salisbury Crags in Edinburgh

  

  Thousands of Yes voters gathered in Glasgow's George Square yesterday on the final day of campaigning 

  

  Better Together voters in kilts and tartan hats and scarves wave Union Jacks in Glasgow's George Square 

  

  Despite what could be a record turnout of a reported 95 per cent, the future of Scotland relies on undecided voters

  
  

  Taking them into account, the No campaign is backed by 49 per cent, Yes on 47 per cent and ‘don’t knows’ on 5 per cent. The figures are rounded up. 

  That represents a slump in support for the No campaign of five percentage points from August, while Yes is up seven points.

  Turnout for the referendum is now likely to be extremely high, with 95 per cent claiming that they are certain to vote. 

  While this figure is higher with those aged 55 and over who traditionally are more likely to turn out – 97 per cent – it is still very high across all age groups, including those aged 16 to 24, where 90 per cent claim they are certain to vote.

  The record for any UK referendum was set by the 1998 vote in Northern Ireland, in which 81 per cent of voters took part. 

  It could even break the record for any UK-wide vote – the 84 per cent turnout in the 1950 general election.

  Today's figures come after both sides said they were confident they would win earlier this week. 

  Appearing on the Andrew Marr Show, Alex Salmond admitted to taking a 'premature victory lap' while Alistair Darling said he was 'confident' the No campaign would remain part of the UK. 

  Thousands flooded Scotland's major cities yesterday on the final day of campaigning.

  Crowds swelled in Glasgow's George Square which saw the heaviest police presence, while a planned march through the cobbled streets of Edinburgh led Yes voters to gathering at the Scottish Parliament.