Nicola Sturgeon is on course to command an overall majority in the Scottish Parliament after the latest Sky News poll showed her party’s ratings up sharply in the last month.

Alex Salmond’s breakaway Alba Party registered just 2% support in the new poll by Opinium for Sky News, meaning it currently has a level of support unlikely to translate into a single seat in Holyrood after 6 May.

Alba, launched just two weeks ago in an attempt to secure a “supermajority” for independence, has not dented the SNP vote according to this poll, which has risen in recent weeks as the Scottish Parliament campaign got under way.

Instead, Labour and the Tories have fallen back in the last fortnight.

Labour is down despite improving favourability ratings for Anas Sarwar, the Scottish party’s newly elected leader, and despite the public judging he had a strong performance in the first TV debate.

In the Holyrood elections all the electorate get two votes, one for their constituency MSP and another for their regional member.

When choosing a constituency MSP, the Opinium poll found 53% chose the SNP, up seven percentage points from last month.

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Then 21% chose the Conservatives, down three, 18% Labour, down two, and Lib Dems unchanged on 6%.

In the regional vote, 44% chose the SNP, up two, the Conservatives were unchanged on 22%, Labour down two on 17% while Alba registered 2% support in the first Opinium poll since it was formed.

If these results are translated roughly into seats, the SNP will get an overall majority in the Scottish Parliament of 13.

The SNP would have 71 seats, while the Conservatives would be on 27 seats, Labour on 21, the Greens on 6 and Lib Dems on 4.

On these results Alba is unlikely to have enough support to get a single seat.

This calculation could be subject to big shifts from comparatively small changes to the voting share, however.

The poll suggests Scots are wary of Mr Salmond’s new party.

Voters respond negatively towards a coalition between the SNP and the Alba Party, with 15% thinking it would be good for Scotland but 63% bad.

This compares to a coalition between the SNP and the Greens which 41% think would be good and 41% think bad.

The boost in SNP support has not translated into a boost in support of independence, which still has 51% in favour of Scotland breaking away from the UK to 49% against once “don’t knows” are excluded.

Despite not seeing an increase in Labour’s voting intention numbers, MrSarwar has seen a significant boost to his favourability ratings, with a +10 rating, as Mr Salmond and Douglas Ross have declined on -60 and -31 respectively.

Ms Sturgeon remains the most popular politician on +10.

Mr Sarwar is also seen as having done a good job in the debate where 62% think he did well and 28% badly, whereas Ross is seen to have done badly with 28% saying he did well and 62% badly among those who watched or saw highlights.

However, Ms Sturgeon is still seen to have performed best with 67% well and 27% badly.

:: Opinium interviewed 1,023 Scottish adults online between 1 and 6 April.