TWO-THIRDS of Scots want the unionist "vow" on more powers for Holyrood to extend as far as devo max, meaning MSPs running everything except foreign affairs and defence, according to a new poll commissioned by the SNP.

The Panelbase survey found 66% of respondents wanted the commission on more powers headed by Lord Smith of Kelvin to produce devo max, with 19% opposed and 15% undecided.

Devo max had majority backing from supporters of all parties, with 59% of those who voted LibDem in the 2011 Scottish election in favour, 60% of Tory voters, 62% of Labour voters, 71% of Green voters and 79% of SNP voters.

It was backed by 71% of men, 62% of women, all age groups and all socio-economic classes.

Asked about individual powers, 75% said the new powers should include control of the welfare and benefits system, 71% said "all taxation", 68% said oil and gas revenues from Scottish waters, 68% said the state pension, and 54% wanted the vow to include broadcasting policy.

In addition, 72% of those polled wanted a guaranteed consultation between the Scottish and UK Governments on the UK stance in future negotiations with the European Union.

Lack of consultation by London on EU policy affecting Scottish fishermen has long been a bugbear of the SNP.

The 2013 Scottish Social Attitudes survey, which reported in February, found support for devo max at 32%, compared to 31% support for independence and 28% for the status quo.

However, 42% of people gave devo max as their second preference, and outright support for maximum devolution rose significantly in the closing weeks of the referendum, with even a majority of No voters saying they wanted Holyrood to control tax and welfare decisions.

Finance Secretary John Swinney, who is one of the SNP's two representatives on the Smith Commission, said: "These are extraordinarily positive findings, showing strong support for extensive new powers - including control of all taxation and the welfare system in Scotland - right across Scottish society and across the political spectrum.

"There is also overwhelming support for the Scottish Government to be consulted about the UK's stance in European negotiations.

"In the referendum, 45% voted for independence, and Westminster promised 'extensive new powers' to the 55% who voted No.

"It is clear people want the fullest possible transfer of powers from Westminster to Scotland, so we are able to use our abundant resources to build a fairer, more prosperous, society."

The "vow" at the heart of the more powers debate was signed by David Cameron, Nick Clegg and Ed Miliband, and published two days before the referendum on the front of the Daily Record.

The trio said they would ensure Holyrood had "extensive new powers" after a No vote.

After Scots rejected independence by 55% to 45%, Alex Salmond said he believed the vow had been a key factor in the result, and that it was imperative that the UK parties delivered on it.

However, because Labour, the Tories and the LibDems have different ideas on what the new powers should be - and are unable to agree even on the devolution of income tax - no details were ever spelled out before the referendum.

The SNP is now trying to capitalise on the lack of a common plan among the unionist parties by promoting devo max as the public's choice, even though no other party has suggested it.

The Panelbase poll also suggested some confusion among voters about devo max.

Support for devolving specific powers was often lower than for devo max in general, even though devo max implies those powers would be devolved.

For instance, although 60% of Conservative voters backed devo max, less than 50% of them supported the devolution of the state pension, or oil and gas revenue or broadcasting policy, which would all result from devo max.

Pollster Professor John Curtice, of Strathclyde University, said there was a "health warning" on the wording of the devo max question, as it "pushed" people to agree.

The question asked: "During the recent independence referendum campaign, the UK leaders of the Conservative, Labour and Liberal Democrat parties published a vow promising 'extensive new powers' for the Scottish Parliament in the event of a No vote.

"Do you believe that these extensive new powers should include ...

"Control of all areas of government policy except for defence and foreign affairs, which is sometimes referred to as devo max?"

However, Curtice said other polls also showed clear support for more powers, though there was disagreement about how they should be used.

"The instinctive reaction of the Scottish public is that domestic affairs should be decided in Edinburgh," he said.

But he warned that Lord Smith's Commission was in the "somewhat ridiculous" position of trying to find an agreed plan in a few months, about something on which there had been relatively little public debate, and on which there were fundamental differences between parties.

"He's certainly got a hell of a job. The Commission needs to get agreement on A) what the parties want, and B) come up with something that meets people's aspirations. Pretty tough."

The Panelbase poll was conducted between September 29 and October among 1049 Scottish residents aged 16 and over.