SINN Féin's Michelle O'Neill last night said a referendum on Irish unity was the "only solution" to a no deal Brexit.
Speaking at a public debate during the Labour Party conference in Brighton, Ms O'Neill said that a "no deal Brexit and the Good Friday Agreement are mutually incompatible".
"There is a deal on the table and it includes the Irish backstop which must be maintained as an insurance policy and guarantee to protect peace, jobs and the all-Ireland economy and structures," she said.
"In the event of a no deal Brexit, however, a referendum on a united Ireland is an obvious option which must be on the table.
"There is a growing sense that circumstances are now rapidly changing which will inevitably lead to the final break-up of the current constitutional structures."
Ms O'Neill, Sinn Féin's vice-president, also said the "issue of Irish unity has taken on a new dynamic because of Brexit".
"This cannot be ignored," she said.
"The political momentum is moving in that direction.
"The EU has said in the event of Irish reunification the north would automatically rejoin the EU.
"People are coming to the Irish unity conversation not to become republicans and nationalists, but to remain Europeans - and the opportunity to stay in the European Union, through separation from Britain."
