An interim employment tribunal has ruled in favour of a sacked convener at the Grangemouth refinery, his union has said.
Mark Lyon is claiming unfair dismissal after being sacked by Ineos, which operates the site, in February.
The tribunal said it was likely Mr Lyon would win the case when it goes to a full hearing. It ordered Ineos to pay his wages until then.
The company said it still believed Mr Lyon was guilty of repeated misconduct.
The Grangemouth complex was the site of a bitter industrial dispute between the union and Ineos last year
The dispute centred on the treatment of another union convener, Stevie Deans.
Unite had previously claimed Mr Lyon was "tried in his absence" before being sacked in February.
The union had also said there was significant medical evidence that Mr Lyon was suffering from a serious stress-related illness as a result of the treatment he had "endured" at the hands of Ineos.
Unite said the tribunal was asked to make an interim finding in Mr Lyon's favour in order to "avoid the financial hardship he will face between now and the final hearing over his unfair dismissal for trade union activity".
The union's legal director Howard Beckett said: "We welcome this interim finding which gives Mr Lyon some financial security until the full tribunal where all the evidence will be heard.
"It is a shot in the arm for workers across the country and sends out a clear message that they can be a member of trade union and represent other workers without fear of victimisation.
"Ineos needs to drop its hostility to the workforce and ensure there is no victimisation of workplace representatives before the brain drain of skills at the site becomes a flood that threatens the site's survival.
"Ineos should be in no doubt that we will continue to fight for our members at Grangemouth and pay heed to the interim finding by starting to work with the representatives the workforce has chosen."
In a statement, Ineos said Mr Lyon's dismissal had followed an investigation by the company and a series of disciplinary hearings, all of which it said were in accordance with the company's agreed disciplinary policy and procedure.
It added: "Mr Lyon made a complaint regarding his dismissal to a Scottish employment tribunal.
"An interim relief hearing was held today. The hearing made a number of rulings which the company notes.
"These rulings do not change Petroineos' view that Mr Lyon was guilty of repeated misconduct and that his dismissal was entirely justified, subject to appeal."
Last year's dispute led Ineos to threaten to close part of the site if workers did not agree to a rescue package to help secure its future.
Unite had been threatening strikes over the suspension of Mr Deans, but the union decided to accept the company's proposals, and Mr Deans resigned from his job.
Mr Deans was also chairman of the Falkirk Labour Party, which was embroiled in a dispute over claims that Unite had tried to influence the selection of an election candidate.
An internal report was drawn up for the party, with Unite insisting it had done nothing wrong.
The row led to Labour leader Ed Miliband announcing reforms in the historic link between the party and unions - changes which were agreed by the party's national executive last month.