The British government has said it has no legal requirement and would not be acting in the public interest if it was to set out criteria that would lead to a Border poll.
Under the terms of the Belfast Agreement, the onus for calling such a poll lies exclusively with the secretary of state for Northern Ireland.
They can call a poll "if at any time it appears likely to him/her that a majority of those voting would express a wish that Northern Ireland should cease to be part of the United Kingdom and form part of a united Ireland".
Queens University Belfast academic Prof Colin Harvey pressed the British government in December to publish the criteria it would use to call such a poll.
In his letter to secretary of state for Northern Ireland Brandon Lewis, Prof Harvey asked him to outline who he would consult, what plans he would make and what role the Irish Government would have in a future Border poll.
Prof Harvey, a member of the pro-unity Ireland’s Future group, added: “ If you have concluded that the relevant test has not been met, will you share the information you used in forming this judgement? How often do you review the available evidence?”
The response was sent by the Northern Ireland Office’s (NIO)constitution, rights and healthcare policy group on behalf of Mr Lewis.
The letter states that the secretary of state must “have regard to reasonable factors and make a judgement based on objective, reliable and emperical evidence”.
However, the letter concluded by stressing that the British government did not need to set out the evidence it would use to call such a poll. It cited a High Court judgment received by victims' campaigner Raymond McCourt in April. Mr McCourt's son was killed by the UVF during the Troubles.
He failed in his attempt to get the British government to lay out its policy for holding a Border poll. He complained that the current criteria for calling a referendum on the question of Irish unity lacks transparency.
Prof Harvey described the reply from the NIO as “a disappointing and dismissive response”.
“These are fair and legitimate questions about the future of our shared island. Everyone knows that we are on a pathway towards these referendums taking place. People want answers, and will reach their own conclusions about the role of the Secretary of State,” he said.
“The obvious absence of detailed thought and proper preparation is a major concern, and the lack of clarity remains troubling. The people of this island deserve so much better.”
