Supporters against of the idea of keeping Scotland in the United Kingdom regained a tiny lead over separatists less than a week before Scots vote in an independence referendum, opinion surveys showed today.

A YouGov survey for The Times put Scottish unionists on 52 percent with separatists on 48 percent while a Guardian/ICM poll put unionists on 51 percent and separatists on 49 percent. The number excludes those who said they did not know how they would vote.

"The 'no' campaign has moved back into the lead in Scotland's referendum campaign," YouGov President Peter Kellner said in a commentary on the survey. "This is the first time 'no' has gained ground since early August."

The division issue has gained such a huge importance that finance minister George Osborne, Britain's second most powerful man, cancelled a trip to the G20 meeting in Cairns which takes place the weekend after the vote.

Pollsters have shown an increase in support for independence since late August as the secessionist campaign led by Alex Salmond succeeded in winning over supporters of the traditionally unionist Labour party and some female voters in Scotland.

The erosion of the strong unionist lead has prompted investors to sell sterling, shares in companies with Scottish exposure and British government bonds on fears that the referendum would lead to the division of the UK.

Sterling has fallen 2.5 percent against the U.S. dollar this month and the cost of hedging against near-term swings in value by the British pound jumped to four-year highs on Friday.

In September, investors pulled $27 billion out of UK financial assets. It is the biggest capital outflow since the Lehman crisis in 2008.