Peter Robinson (second left) poses before his speech with Professor Richard English, pro-vice-chancellor for Internationalisation and Engagement, Professor James McElnay, acting president and vice-chancellor of Queens and Professor John Brewer, acting director of the Senator George J Mitchell Institute for Global Peace, Security and Justice at Queens

The former first minister said fixed generational polls would help make the constitutional question less disruptive and the prospect of a referendum less threatening.

But fellow unionists have not responded well to the proposal, with former party colleague Sammy Wilson MP branding the idea “unhelpful”.

Meanwhile, the Irish prime minister has warned that a vote on Irish unity would be “divisive” and “a bad idea”.

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Speaking ahead of a historic visit to the Orange Order headquarters in Belfast yesterday, Leo Varadkar said he felt a border poll would be won by those who wish to remain in the union.

“While the Good Friday Agreement provides for the possibility of a border poll, I don’t think the time or the conditions are right,” the taoiseach said.

While DUP MP Mr Wilson welcomed Mr Varadkar’s comments, he was critical of his former party leader’s suggestion of regular border polls.

He told the News Letter: “This issue of continual border polls would be a bad idea. It is destabilising, as we have seen in Scotland.

“I am not so sure that even having discussions about a border poll at the minute is helpful. The conditions for a border poll have not been met so why do we even need to talk about it?

“It is quite clear there is no appetite for it, and even though I would be very confident – as Leo Varadkar is – that the unionist opinion would win in a border poll, I just think that we do not need to introduce yet another area of contention into the mix.”

Meanwhile, Ulster Unionist MLA Doug Beattie said Mr Robinson “cannot simply pick and choose” elements from the Belfast Agreement.

He added: “The Belfast Agreement set out the conditions for a border poll and those conditions have not been met. Peter Robinson is trying to amend the agreement to suit what he feels is right. That is not helpful.

“I don’t think his calls for fixed border polls is a rational approach unless we start to renegotiate the terms of the agreement all over again.”

Agreeing with the taoiseach’s assessment of the constitutional situation in Northern Ireland, the Upper Bann MLA added: “Leo Varadkar is absolutely right in saying that any border poll now would be won by those wishing to stay within the union.

“I think it would be extremely divisive and would not be in the best interests of the country.”

TUV leader Jim Allister said it was “questionable” why any unionist would “lend credence” to the idea of fixed generational border polls.

“There is a certain danger in what Mr Robinson is saying,” he told the News Letter.

“It is perfectly clear to me that NI is a settled part of the UK by the will of its people and the only ones who want to change that are those who previously tried to do so by terrorism, and now seek to do so by political means.