NICOLA Sturgeon has appealed to No voters to back the SNP, as a fresh poll revealed tactical voting could be Scottish Labour's only hope of preventing an electoral wipe-out a week from today.

Ms Sturgeon urged Scots to "come together as a country" on May 7, claiming a large contingent of Nationalist MPs would make the nation's voice heard "louder than ever" at Westminster.

Her message was dismissed by former Labour Prime Minister Gordon Brown who, in what is expected to be his final major speech of the election campaign, said patriotism should not be confused with nationalism.

Ms Sturgeon sought to broaden the appeal of the SNP amid growing signs that hundreds of thousands of Scots could vote tactically to limit her party's gains.

An Ipsos MORI poll for STV News showed support for the SNP rise to 54 per cent, putting it on course to win all 59 seats in Scotland.

However, the survey also showed that Labour and the Lib Dems stood to benefit from widespread tactical voting.

Only 14 per cent of voters have Labour as their first choice, according to the poll, but a further 30 per cent say they might vote for Jim Murphy's party if they believe it can win in their constituency.

A quarter of voters said they were prepared to switch allegiance to the Lib Dems.

Ms Sturgeon yesterday tried neutralise the threat of tactical voting, insisting the election was "emphatically not about independence".

Addressing a breakfast meeting of women business leaders in Glasgow, she urged Yes and No voters to back the SNP.

"If we come together as a country, we can seize this historic moment to shift the balance of power from the corridors of Westminster to the communities of Scotland.

"By voting SNP, we can make our nation's voice heard like never before.

"Together we can unite to make Scotland stronger and to make Westminster better," she said.

The Ipsos MORI poll put support for the SNP at 54 per cent among those certain to vote, up two points since January.

Labour slipped four points to 20 per cent; the Tories rose five to 17 per cent, and the Lib Dems dropped a point to five per cent.

Ms Sturgeon claim that SNP influence at Westminster would benefit Scotland is helping drive her party's surge in the polls.

A clear majority of Scots (69 per cent) believe it would be good for Scotland, while 60 per cent believe it would be good for the UK.

The view is shared by nearly half of all Labour supporters and Lib Dem supporters.

The poll also suggested Ms Sturgeon's personal popularity was boosting her party's fortunes.

Her approval rating - the difference between those who believe she is doing a good or bad job - was 48 per cent, streets ahead of her rivals, as 71 per cent of Scots said they were satisifed with her performance.

Scottish Labour leader Jim Murphy's rating was minus 19 per cent, a slump of 15 per cent since January.

Separate polls also brought good news for the SNP yesterday, with one suggesting women were much more likely to support than Nationalists under Ms Sturgeon than they were under Alex Salmond.

Mark Diffley, the director of Ipsos MORI Scotland, said: "While the numbers of seats each party will win next week remains unclear, it is likely that the SNP will make significant gains.

"For Labour, while support has fallen since our last poll in January, they will hope that those who remain undecided and those who are prepared to vote tactically, will back them and help to minimise the loss of seats."

Ms Sturgeon said next week's poll was a "collective opportunity" to end three party politics at Westminster.

She said the SNP holding the balance of power would create a "better, more representative parliament, leading to better government not just for Scotland but for every part of the UK."

Labour this week launched an all out attack on the SNP, warning its MPs would seek to engineer a second independence referendum.

The move was seen as a bid to maximise support from anti-SNP tactical voting.

Scottish Labour deputy leader Kezia Dugdale said: "The choice facing Scots next week is clear.

"We can vote for Labour to take the road to a fairer and better nation for working class families.

"Or we can back the SNP and go down the road to another referendum.

"When there is so much inequality in our country, the priority right now just can't be another drawn out referendum campaign."