London: Britain's more than 300-year-old union with Scotland may survive today's historical referendum by a narrow margin, a new survey showed.
Supporters of a united UK were maintaining a narrow but steady lead of four points; 52 per cent to 48 per cent, over the supporters of Scottish independence, YouGov's final pre-election survey for The Times and Sun newspaper showed.
However, the race was still too tight for YouGov's analysts to be confident in calling it. Instead, the polling company only predicted an 80 per cent probability that the UK will hold together giving a breakaway Scotland a 20 per cent chance.
Voters have a simple "Yes" or "No" choice to the question: "Should Scotland be an independent country?" Whatever the result, British politics is set to change forever after the referendum.
In the short-term, British Prime Minister David Cameron would have most to lose if Scotland votes to leave the UK. Some Conservative MPs believe he could even lose his job, according to The Independent.
Though, a "Yes" verdict may prove disastrous for the UK's Labour Party, which currently holds 41 of Scotland's 59 constituencies - which would no longer send MPs to Westminster after "independence day", which is due to happen in March 2016 on Scotland's First Minister Alex Salmond's timetable.
Politicians on both sides of the divide have risked their careers and thrown their weight behind 'Yes' or the 'No'
Meanwhile, voting in Scotland was in full swing today and people have been queueing up since morning to register their vote in the historic referendum.
Nearly 97 per cent of the electorate, adding up to 4,285,323 people, have registered to vote at 2,608 polling places across the country until 22:00 (local time) today.
Once the polls have closed, ballot papers will be counted in each of Scotland's 32 local authority areas. These will include votes cast from the 789,024 postal vote applications, which was the largest volume of registration for postal votes ever in Scotland, according to the BBC.
Results are expected early tomorrow morning.