THE SNP is on course to increase its majority in next year's Holyrood election according to a new poll which suggests Labour will not win a single constituency. 

The TNS survey shows support for the Nationalists has increased since the party's stunning UK election victory in Scotland last month.

Six out of 10 Scots plan to vote SNP in their constituency vote on May 5 next year and half will back Nicola Sturgeon's party in the regional ballot.

According to the Scotland Votes online seat calculator, the latest polling figures put the Nats on course to win a second outright majority.

They are set to take 73 seats, four more than they won in 2011, beating Labour into a distant second place with 25 seats, down 12.

The Conservatives would take 17 seats (up two) while the Greens would become Holyrood's fourth party with a record 10 seats, up eight from their present tally.

The Lib Dems would hold four of the five seats they have now.

The SNP would win 70 of Holyrood's 73 constituencies, with the Tories taking two and the Lib Dems one.

All of Labour's seats would come from the regional lists, as the party faces the prospect of losing all 15 constituencies it won in 2011.

TNS surveyed 1031 Scots aged over 16 between May 13 and 30.

Among those certain to vote, and discounting don't-knows, 60 per cent of Scots plan to vote SNP in the constituency vote, up from 50 per cent in 2011. 

A further 19 per cent plan to vote Labour (down 13 points); 15 per cent Conservative (up one) and three per cent Lib Dem (down five).

In the regional vote for the remaining 56 seats - where the Greens focus almost all their effort - 50 per cent said they would vote SNP (up six points on 2011); 19 per cent Labour (down seven); 14 per cent Conservative (up two); 10 per cent Green (up six); five per cent Lib Dem (no change); and two per cent UKIP (up two).

Turnout is set to be considerably higher than four years ago, possibly explaining some of the SNP's strong showing. 

TNS found 67 per cent of those questioned were certain to vote, compared with 50 per cent who bothered to cast their ballot in 2011.

Asked about the forthcoming referendum on Britain's membership of the EU, 49 per cent said they would to stay in; 19 per cent to leave and 26 per cent were undecided.

Tom Costley, head of TNS Scotland, said: "Clearly there is a long way to go until the Scottish Parliament elections, so it is too early to tell whether the rise in support for the SNP represents a continuing trend, or whether it reflects a 'honeymoon' period with the party's new Westminster MPs.

"The strong support for continuing EU membership may reflect both this factor and the strong advocacy by Nicola Sturgeon, who remains a popular figure: the case for the EU has yet to be tested in the full-blown political campaign that will precede the referendum."

Reflecting on last month's UK election, only 27 per cent believed Scotland would have a lot of influence at Westminster.

Forty three per cent said the result made independence for Scotland more likely.

SNP MSP Stewart Maxwell said: "This is an excellent poll, highlighting the SNP's extraordinarily positive ratings after eight years in government."

The Greens - who like the SNP have seen membership soar since the independence referendum - also welcomed the findings.

Scottish Green MSP 

Alison Johnstone said:

"Everyone takes polling with an added pinch of salt these days but we do believe we're in a strong position to turn these consistent numbers into elected MSPs working hard for communities. 

"We have excellent candidates in place and branches of activists out campaigning to deliver our best ever result at Holyrood."

She added: "It is clear that the Scottish Parliament needs a main opposition party that is constructive yet challenging, and the Scottish Greens are ready for that role."