He added: "On the Negative side, the Northern Ireland protocol - Northern Ireland has been carved off the rest of Great Britain.
"I think it's really clear now that Government's policy is a united Ireland but that's for another day."
The British Government has already been warned the Brexit and the subsequent protocol agreed with the European Union on Northern Ireland could pose a serious threat to the Union.
Brigid Laffan, Director of the Robert Schuman Centre for Advanced Studies, warned Brexit may set a precedent for Irish nationalists to push for independence.
Prof Laffan said: "I fully agree there won't be a border poll this year, next year, or in five years but there will be a border poll in the next ten years to 15 years.