Scottish support for independence seems to be waning, a new opinion poll has showed, just 5 days before Scotland votes on whether to separate from the rest of the United Kingdom.

The survey by the pro-union "Better Together" campaign found support for staying in the United Kingdom was at 54 percent, while 46 percent were planning to vote for independence on September 18, once undecideds were excluded.

"This poll suggests that 'No' are in the lead but that the race is far from over," Blair McDougall, campaign director of the "Better Together" campaign told the AFP news agency.

Saturday's poll comes as a boost to the anti-independence campaign after the latest "poll of polls" on Friday showed the vote remained on a knife-edge, with just 51 percent support for staying in the UK.

While polls had consistently shown strong leads for the "No" campaign to reject independence, a recent surge in support for "Yes" has prompted some investors to sell the pound and the shares of Scottish companies over concerns about the economic ramifications of a split.

Former UK Prime Minister Tony Blair, decided to wade into the debate saying a breaking up of the UK would not be a sensible step.

"I hope Scotland votes to stay part of the United Kingdom," Edinburgh-born Blair said at a security conference in the Ukrainian capital of Kiev.

"For all the reasons given by all the party leaders of the UK, in the 21st Century to rip up the alliance between our countries would not be sensible, politically, economically or even emotionally."

Scotland votes on Thursday whether to end a 307-year-old union with England and break away from the United Kingdom.

Al Jazeera