LONDON (Reuters) - More Scottish voters are favouring independence as criticism grows that the campaign to keep them in the United Kingdom is too negative, according to an opinion poll on Wednesday.
A TNS poll found support for Scotland to vote to leave the United Kingdom after more than 300 years in a Sept. 18 referendum nudged up one percentage point to 30 percent while opposition rose one point to 42 percent, leaving 28 percent undecided.
But although the headline figure showed little change, the poll found that among those certain to vote, 35 percent would opt for independence against 44 percent opposition, narrowing the gap between the two sides to nine points, its lowest since the TNS poll began last September when the gap was 22 points.
The poll also found a marked difference in how the two sides were seen to be handling the debate.
Over half of 996 respondents, or 53 percent, said the pro-UK "Better Together" campaign was negative while only 29 percent described the independence "Yes Scotland" campaign as such.
Better Together, led by former British finance minister Alistair Darling, has been accused by its critics and even by some supporters of being too negative over North Sea oil, banks and currency, rather than pushing the union's strengths.
This has prompted calls for a change in approach by Better Together as polls narrow while independence campaigners have used the criticism to accuse their rivals of being in disarray.
Tom Costley, head of TNS Scotland, said even among Scots who intended to vote against independence, more agreed than disagreed that the campaign had been negative.
"As the electorate usually claims to dislike negative campaigning, this poll suggests that Better Together may need to consider adopting a more positive tone to its campaigning in the run-up to Sept. 18," Costley said in a statement.
The poll comes as Better Together had started to draft more people into its campaign to help bolster support and woo the large number of undecided voters away from the pro-independence stance of the ruling Scottish National Party (SNP).
Former Labour Prime Minister Gordon Brown, who is respected in Scotland, has started to take a more active role in fighting against independence and Labour's foreign affairs spokesman Douglas Alexander was in Scotland for a speech on Monday.
"As we approach the final stages of the campaign, Alistair (Darling) is bringing more and more people into the team. This is just what you would expect," said a Better Together spokesman.
"The Scottish National Party will be throwing everything at breaking up Britain. We must make sure that we have our best people involved so that we can win the arguments."
(Reporting by Belinda Goldsmith; Editing by Angus MacSwan)