Former Taoiseach John Bruton has said a trade war between the United Kingdom and the European Union would have a "very severe effect" on Ireland.
Mr Bruton said a trade war is his "number one worry" for Ireland currently, and while it hadn't happened yet, "it could happen quite soon".
Mr Bruton was addressing a Cambridge seminar series online on the future of the island of Ireland on Monday.
The former Fine Gael leader also said he thinks the country is "a good distance away from Irish unity".
Mr Bruton said the State was facing "a very fundamental moment" this week as the UK contemplates triggering Article 16 of the Northern Ireland protocol.
He questioned whether the ultimate intent of the UK government was to “permanently destroy” the protocol and create “a huge gap” in the border of the European single market.
"What I think Boris Johnson has discovered is that Brexit works to get votes and the tougher you are with the European Union the more popular you are in certain categories of English public opinion... He's been rewarded for being tough politically so far, therefore he will go on doing that until it suddenly becomes the case that he's not being rewarded for that anymore. I think, at a very simple level, that's part of it," Mr Bruton said.
"However, at a deeper level, there is probably in some quarters of the United Kingdom and particularly in England, a wish to basically destroy the European Union, to divide the European Union because British and English grand strategy over the last 500 years has always been that of maintaining division on the continent of Europe, not allowing any capacity to unite on the continent of Europe and to keep the continent disunited."
Mr Bruton said Irish politics is going through "an unusual phase" at the moment, with Fianna Fáil and Fine Gael in coalition. He said the coalition seemed to be working "remarkably well" with little friction adding "I wouldn't write off at all the prospect of this current government in Ireland being re-elected".
When asked about Irish unity, Mr Bruton said: “I think we’re a good distance away from Irish unity. I think the important unity in Ireland is the unity of mutual respect between the two traditions that exist on the island.”
“Those two allegiances are not about to disappear,” he added. “I don’t think that a border poll which voted for a united Ireland by 51 to 49, similar to the famous referendum on Brexit, in its closeness would give us stability.
“I do not think that the minority, if the unionists found themselves in the minority, would settle down to being governed from Dublin.
“I don’t think that public opinion in the Republic of Ireland is ready to make the sacrifices of lives as well as money that would be necessary to sustain unity if there was a very determined renouncement minority in the north east of the island who just didn’t accept it.”
Mr Bruton said he would “of course” like to see a united Ireland but that he didn’t think it was a practical vision in current or foreseeable circumstances.
“I think we need realists in Ireland and I think unionists also need to come to terms with the fact that they may be British in their allegiance but Irish in their geographical location, they are Irish and they need to get on with the rest of us on the island of Ireland,” he said.
Mr Bruton added “we have had too much identify politics, we need practical politics”.