A NEW poll on Scottish independence has shown that support for remaining part of the Union appears to be on the wane.

A survey commissioned by the pro-independence group Progress Scotland at the start of October shows that 51% of Scottish voters who expressed an opinion wished to remain part of the UK.

But that has shrunk from the 58% that supported Scotland remaining in the Union when a similar poll was conducted just before the original March deadline for exiting the EU.

The Survation poll of Scottish attitudes over Brexit similarly found that the numbers who say that they "completely support Scotland staying part of the UK" had dropped in the same period from 40% to 37%.

The full findings are revealed in a comparison of the October and March surveys carried out for Progress Scotland, and seen by the Herald.

READ MORE: Support for Scottish independence rises to 50%, according to new poll

Some 40% offered some level of positive support for Scotland becoming independent, according to the latest 'sliding scale' survey, identical to the March poll.

But those who say they "completely support" Scotland become independent has gone up over that six months from 24% to 26%. Some 4% of those wholehearted backers of independence were No voters in the 2014 referendum.

In November last year, a Survation poll for Scotland in Union, which is opposed to Scottish independence showed further support for Remain. When asked if there was a new Scottish independence referendum tomorrow should Scotland stay in the UK, 54.85% said Remain, with 36.02% plumping for Leave with around 9% either undecided or refused to register a decision.

Last week, Scotland's first minister insisted that a legal referendum is the only way for the country to win independence.

She dismissed claims that the SNP winning a majority of Scottish seats in a general election would be enough for independence to be declared.

There was "no easy or shortcut route to independence" and that a future referendum had to be "beyond any doubt in terms of its legitimacy".

READ MORE: Ian Blackford says Scottish independence vote 'has to happen' next year

But she insisted that independence was now closer than ever.

She has repeatedly said she wants to hold a second referendum on independence next year - but the move has been ruled out by the UK government.

The latest Survation poll of 2,032 people aged over 16 in Scotland also revealed some 63% agree that Brexit makes independence more likely - showing no change from March.

When Scots were asked if the UK leaves the EU without a deal, would they be more likely to vote for independence in a future referendum, 59% agreed in that latest poll, up from 56% in March.

According to the latest poll, more than half of Scots (55%) think there will be another vote on independence within the next two years -a rise from the 48% who believed that in March.

The Survation polls on support or otherwise for Scottish independence for Progress Scotland did not seek a straight Remain or Leave option. Instead, voters were asked to provide a depth of feeling about independence or staying part of the Union using a scale from zero to ten.

The analysis falls more in line with the Panelbase survey for The Sunday Times Scotland which last week found support for Scottish independence had risen to 50%.

The 50% figure backing independence marks a five point increase on the 45% Panelbase registered on average in its polls last year, which mirrored the 45% yes 55% no result of the 2014 independence referendum.

Angus Robertson, the former leader of the SNP's Westminister group in Parliament, who is the managing director of Progress Scotland, said after some of the latest poll results were produced on its website: “These poll results show that Brexit is having a major impact on general public opinion on the timing of a second independence referendum, and particularly on swing voters who are open-minded or undecided on Scottish independence.

“A clear majority believe that Brexit makes Scottish independence more likely and that their views have changed about Scottish independence."

The Press Association previously reported that the Progress Scotland poll showed that Scots are "more likely to have shifted towards remaining part of the UK rather than backing Scottish independence".

Scottish Conservative constitution spokesman Adam Tomkins had said when the original figures - that came without the March comparisons - were revealed: "It's no wonder these independence campaigners want to keep the results of this poll quiet.

"Progress Scotland aren't usually slow to trumpet their findings so it's interesting that they've been so secretive about this particular survey.

"Like the vast majority of polls, it reveals again that more Scots want to remain in the UK than to leave it.

"And, far from gaining momentum, it seems the Yes campaign is losing supporters at a higher rate than it's gaining them."