The British National Party (BNP) in the South West is mounting a legal challenge after a member resigned from a Devon parish council.
The BNP says that Mr Pirnie has been treated unfairly
BNP member Peter Pirnie was co-opted onto Kingswear Parish Council earlier this month.
But he resigned after a row erupted over whether he had misled councillors about his political intentions.
The BNP says Mr Pirnie has been treated unfairly and is pursuing a case under the Equality Act 2006.
Bus driver Mr Pirnie, 49, unsuccessfully stood for a seat on the Kingswear Village ward in May.
After the election the council advertised for members because only two people had come forward for the Hillhead ward, which normally has five councillors.
Mr Pirnie was one of three people to apply for the posts, and councillors took a vote and co-opted all three on to the council.
Mr Pirnie described himself in the election as an independent, said the BNP.
He then described himself as a "BNP councillor" in a BBC interview.
His appointment as a BNP councillor was also announced on the BNP website.
That led to a row in which he was accused of misleading the parish council and he resigned last week.
Peter Mullins, South West regional organiser of the BNP, said: "Mr Pirnie is an ideal member of the parish council and it seems a shame that has not been allowed to take up the post.
"He is a decent sort of guy. He's lived there for 30 years and wanted to do something for the community."
No-one was available for comment from the parish council.