Opponents of a planned wind farm on moorland to the north of Swansea are confident the scheme will have to be delayed after a Welsh Government Minister ruling.
Earlier this month RWE Innogy UK said construction of 16 turbines at Mynydd y Gwair in Felindre would start next month.
But behind the scenes a row has been simmering over an access road.
Campaigners, some of whom have been fighting the development for 25 years, were adamant that there was no consent in place for an access road off the A48 at Bolgoed Road, Pontarddulais.
And in a letter to Brigitte Rowlands, secretary of West Glamorgan Commoners’ Association, Cabinet Secretary for Environment and Rural Affairs Lesley Griffiths confirmed that the disputed piece of land was not covered by the application she granted.
She said that it covered de-registering certain land as common land and registering other land as replacement common land in relation to the wind farm.
And in reference to the issue raised by Mrs Rowlands, the Minister said: “The common land boundary you have identified between the two areas of release land was not part of my consideration as it did not form part of the application for the release and exchange of common land.”
Ioan Richard, Mawr ward member on Swansea Council, said Innogy had dropped a clanger.
“The developer cannot proceed with work on this section until one of three options are formalised,” he said.
They included going through the land exchange procedure or making a fresh application, all of which would, he said, delay the scheme.
Pontarddulais Town Council member John Miles said: “They will have to submit a planning application not to the planning authority, but to the Assembly Government. Whatever option they take, there will be a delay. We want to see the scheme adhered to, fair and square.”
Mr Miles said that another bat survey may have to be carried out to establish whether there was any impact on bats in the area.
The row over the access road reared its head last July after the developer was given Welsh Government approval for the project.
Opponents then claimed that any celebrations were premature because of the road issue.
The firm had already been given the necessary planning consent for the controversial proposal at Mynydd y Gwair in Felindre by the council, but needed the go-ahead to exchange common land to make it viable.
Then the Welsh Government approved RWE Innogy’s common land applications to facilitate the construction and operation of the 33.6MW wind farm.
The final decision, announced by Ms Griffiths, followed the recommendation of an independent planning inspector who led a public inquiry into RWE Innogy’s application earlier last year
Innogy has so far failed to issue its reaction to the letter, but insisted earlier this month that “all consents required are in place”.