Veteran DUP representative Jim Wells has resigned from the party after 46 years.
Mr Wells, a former health minister, told the BBC Nolan Show he could not support the Democratic Unionist Party's candidate in South Down for the Assembly elections, Diane Forsythe.
Mr Wells instead declared his support for a candidate from the rival Traditional Unionist Voice (TUV) in the Stormont elections.
He said: “I have decided I cannot support the candidate that the party executive has imposed on the people of South Down and I have resigned from the party.
“I think that the moment I said that I would not be backing the candidate that was imposed upon us, it was inevitable.
“I took the decision late last night to contact the party leader, the party secretary and the chief executive and let them know that after 46 years I have gone as a DUP member.
“I feel very strongly about this.”
Mr Wells, who has been the DUP’s Assembly representative in South Down since 1998, has called on voters to give their first preference to Harold McKee of the TUV on May 5th.
The DUP responded by stating the election was about more than “mere personalities”.
Mr Wells found out earlier this year he had not been selected as the party’s candidate for the South Down constituency after Ms Forsythe was chosen as the candidate.
Mr Wells had been vocal in his opposition to Ms Forsythe as the candidate, and instead backed a failed bid by former DUP leader Edwin Poots to become the party's candidate in the area.
He has posed in election photographs with Mr McKee and TUV leader Jim Allister.
Mr Wells said: “As I leave the Assembly it is my earnest desire that South Down should continue to have a Unionist MLA whose politics are grounded in conviction and principle.
“Among the candidates Harold McKee is the stand-out candidate with these credentials.
“He holds dear many of the core principles that I upheld in Stormont and is widely and properly respected as a politician of conviction, not expediency.
“Accordingly, I recommend him to those who faithfully supported me at the polls over the years and urge them to vote McKee 1.”
Mr McKee said Mr Wells had been “abandoned by his own party”.
He added: “I am delighted to have his support and gratified that a broad swathe of unionism is uniting behind me as the standard bearer of principled unionism.”
TUV leader Jim Allister said: “At critical times in Stormont, Jim Wells was often the only MLA prepared to join me in doing what was right.
“In December 2020 we were the only MLAs to speak and vote against 45 EU regulations essential to bedding in the iniquitous [Northern Ireland] protocol.
“Putting party advantage before principle would have been easy, but Jim did the right thing and likewise today in backing Harold he is putting principle before party.”
A DUP spokesperson said: “This election is much more important than mere personalities. The seat totals after the count will decide whether NI goes in the right or wrong direction and our priorities for the next five years.
“Diane Forsythe secured the DUP’s best ever result in South Down in 2017.
“She is a young mother, rooted in the Mournes with a plan for South Down. Diane will focus on what matters to people.” – PA