The former Ulster Unionist Party deputy leader John McCallister has said he has resigned from the party following the decision to field a unionist unity candidate in Mid Ulster.
The former Ulster Unionist Party deputy leader John McCallister has resigned from the party.
Mr McCallister said he informed UUP leader Mike Nesbitt and his constituency association of his decision on Thursday.
It follows the DUP and Ulster Unionists' decision to back an agreed candidate to contest the Mid Ulster by-election on 7 March.
He said the party leader had not attempted to make him change his mind.
Nigel Lutton - the son of a former RUC reservist shot dead by the IRA in 1979 - will be the unionist unity candidate.
Mr McCallister made his announcement on BBC NI's politics programme The View.
However, the strategy of cooperation has divided the Ulster Unionist party.
He said he would sit as an independent unionist in the Assembly.
Mr McCallister revealed on BBC NI's politics show, The View, on Thursday evening, that he would quit.
Mr McCallister's announcement follows the decision to select Nigel Lutton as the unionist unity candidate for the by-election in Mid Ulster.
"It is nothing personal about Nigel. It is not personal for me. It is about the principle," he said.
In a letter to Mr Nesbitt, Mr McCallister said he had first voted for the UUP in 1992, because of the party's values and had "no interest in supporting other narrow expressions of unionism, committed as they were to confrontation and triumphalism".
"I disagree strongly about the principle of unionist unity and I don't want to be a part of that."
He said that since becoming an MLA in 2007 he had sought to ensure that these values were "central to my words and actions as a political representative".
Mr McCallister will remain as an independent unionist.
'Grave damage'
Mr Lutton was described by the Ulster Unionist and DUP leaders as an ideal candidate. He is expected to bring victims' issues to the fore.
In 2007, it was alleged in Parliament under privilege by a DUP MP in 2007 that Sinn Féin's Francie Molloy, the party's candidate in the by-election, was suspected by police of being involved in the murder of Mr Lutton's father, Frederick, an allegation strongly denied by Mr Molloy.
In his resignation letter to Mr Nesbitt, Mr McCallister said he had first voted for the UUP in 1992, because of the party's values and had "no interest in supporting other narrow expressions of unionism, committed as they were to confrontation and triumphalism".
The South Down assembly member said that since Mr Nesbitt's election as leader he had shared with him his "grave concerns over the direction" in which he had "been taking the party".
The South Down assembly member said that since Mr Nesbitt's election as leader he had shared with him his "grave concerns over the direction" in which he had "been taking the party".
"Your failure to articulate and communicate a distinctive UUP stance - based on Ulster Unionism's core values - on last year's parades controversies, on the Covenant centenary, on the Union flag debate, on the misguided Unionist Forum and on the potential of electoral pacts with the DUP has unfortunately inflicted grave damage on the party," he added.
"Your failure to articulate and communicate a distinctive UUP stance - based on Ulster Unionism's core values - on last year's parades controversies, on the covenant centenary, on the Union flag debate, on the misguided Unionist Forum and on the potential of electoral pacts with the DUP has unfortunately inflicted grave damage on the party," he added.
"Under your leadership a profound disconnection has occurred between UUP policy and Ulster Unionist values. The policies have increasingly become alienated from the values which should guide and shape an Ulster Unionist leader.
Mr McCallister accused his party leader of choosing to become "Peter Robinson's junior partner."
"Above all, your determination to act in concert with the DUP - over parades, flags and forum - has significantly contributed to forcing Northern Ireland politics back into the sectarian trenches.
The Mid Ulster by-election due to take place in March was called to replace Martin McGuinness.
"At a time of division and uncertainty in our society, Northern Ireland needed the UUP to set out with courage a pro-Union alternative to the politics of sectarian headcounts.
The SDLP candidate will be Patsy McGlone. Independent Unionist William Frazer, the victims campaigner, has also expressed an interest in contesting the race.
"It gives me no pleasure to say that, under your leadership, the UUP has utterly failed to do so.
"Rather than building a confident and generous pro-Union centre ground, you have opted instead to become Peter Robinson's junior partner."
Mr McCallister said that Mr Nesbitt's "unwillingness" to advance the cause of an opposition in the assembly had "similarly damaged" both the UUP and Northern Ireland politics.
"You have taken no action or measures to move towards the creation of an opposition, offering instead merely half-hearted words," he said.
"The creation of an opposition would not only offer genuine accountability in the assembly. It would also offer an alternative to the politics of the sectarian headcount propagated by the DUP and Sinn Fein.
"Your failure to act on this issue has resulted in a UUP incapable of meaningfully challenging the DUP's current electoral position. "
Mr McCallister said Mr Nesbitt had "abandoned pluralist and progressive pro-Union politics for a backward-looking, insular politics that is in the interests of neither Northern Ireland nor the union".
"The decision to repeat a failed electoral strategy and run a 'unionist unity' candidate in Mid-Ulster demonstrates the extent to which you have decided to abandon any pretence that your leadership can make the UUP a home for pluralist and progressive pro-Union politics," he said.
"'Unionist unity' is an exercise in the politics of tribalism, declaring to voters that our society is forever divided between 'orange' and 'green' blocs. It states that all other political issues and debates can be sidelined, because tribal identities must determine our politics."
