EDINBURGH — Scottish support for independence has declined, a poll for showed on Saturday, widening the lead for the pro-union campaign just 5 days before Scotland votes on whether to separate from the rest of the United Kingdom.

A Survation poll on behalf of 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 Sept. 18, once undecideds were excluded.

The 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.

Survation's last poll on Wednesday showed unionists on 53 percent and separatists on 47 percent. The poll released on Saturday showed 9 percent of Scots were still undecided.

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

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.

The Survation poll found that 40 percent of respondents believed they and their families would be worse off financially in an independent Scotland, with just 27 percent saying they thought they would be better off.