Outgoing Sinn Féin leader Gerry Adams has described Brexit as disastrous for the people of Ireland and warned that it should not be seen as something which can be exploited.
Mr Adams said the British government is "not at all clear" about what its future relationship with the European Union is going to be.
Speaking on BBC's Andrew Marr Show, Mr Adams said the British government is "arguing that they’re going to leave the Customs Union and they are going to leave the Single Market and that will end up a complete disaster for people here on the island of Ireland".
He described the negotiations to move into the second phase of Brexit as a "fudge" and claimed that they were "filled with contradictions".
He also reiterated his hopes of a special designated status for Northern Ireland within the EU, and said it is "doable".
Britain's Home Secretary Amber Rudd, meanwhile, has dismissed threats by Brexiteers of a possible leadership challenge and insisted the government would come forward with proposals for a final deal which could command broad support.
Speaking on the same programme she said: "I have surprise for the Brexiteers which is the (Cabinet) committee that meets in order to help make these decisions is more united than they think.
"We meet in the committee. We meet privately for discussions. I think that we will arrive at something which suits us all.
"There will be choices to be made within that but we all want the same thing which is to arrive at a deal which works for the UK."