Stephen Smellie, the deputy convener of Unison in Scotland, will publicly state his support for a Yes vote in the referendum at the union’s national conference in Brighton.
With exactly three months to go until the referendum on September 18, the pro-independence Yes Scotland campaign published new poll findings showing most people in Scotland want decisions over economic policy and welfare to be taken by the Scottish Parliament, rather than at Westminster.
Excluding those who are undecided, 72 per cent of people want these decisions taken by Holyrood, while 28 per cent believe they should be made in London, the Panelbase study found.
Among Labour supporters, 68 per cent support decisions on economic and welfare policy being made in Scotland, when those who did not know were factored out, with a similar figure of 67 per cent among Liberal Democrat voters.
Mr Smellie will set out his reasons for backing independence when he addresses a fringe event at the Unison conference.
Speaking ahead of his speech, he said: “As a trade unionist I look to see where I will be able to negotiate a better deal. In an independent Scotland the trade unions will be more influential than is possible at a UK level.
“Having spent years arguing for a better, more just and fairer Scotland, I do not believe all those people and organisations who have worked for fairness will let the politicians simply get on with it. In alliance with voluntary groups, communities, churches and progressive forces, trade unionists will be able to ensure that decisions taken by government will be more often in favour of working people, of communities, of sustainability, of peace, of justice. These decisions will be fairer.”
Mr Smellie, who is a Labour member, said a Yes vote would make his party stronger.
“The kind of Labour Party needed to champion interests of working people is more likely to develop in an independent Scotland than in the current UK,” he stated.
“The Scottish trade unions have it in their power to make sure this happens.”
He also hit out at the industrial climate, saying at the moment it could be “difficult, no doubt, to stand up to the rich and powerful people who would not shirk from threatening to destroy our economic base if we do not dance to their tune”.
Mr Smellie added: “That is what happened at Grangemouth [oil refinery] last year. The UK political class have created an environment where companies can do this. However, in an independent Scotland there is a chance to construct a social solidarity that would say to [Grangemouth owners] Ineos and others; we are not prepared to let you destroy our economy, our jobs and our community.”
Yes Scotland chief executive Blair Jenkins welcomed Mr Smellie’s comments, adding: “It is a significant feature of the Yes movement that so many prominent Labour figures are joining the campaign, because they realise that independence is the best way to use our vast wealth and resources for the benefit of all people in Scotland.
“The latest poll shows that 34 per cent of Labour voters currently plan to vote Yes in September - a figure which we believe will continue to grow.
“And new poll findings today show overwhelming support for the proposition that people in Scotland will be better off if decisions about economic policy and welfare are taken in the Scottish Parliament, rather than by Westminster. Excluding people who are undecided, 72 per cent back Holyrood and just 28 per cent favour Westminster - including big majorities among Labour and Lib Dem voters.”