Video: Varadkar invites people of Dublin to elect Durkan as 'Derry man to represent all of Ireland'

Mr. Varadkar claimed that it was not possible for two European Parliament seats accruing to Ireland as a result of Brexit to be allocated to the North.

He was responding to a claim by the Sinn Féin President Mary Lou McDonald that this should have happened.

"It is a pity the Taoiseach did not avail of the opportunity to afford the two additional European Parliament seats to the people of the North. It could and should have been done," claimed Deputy McDonald.

But Deputy Varadkar replied: "With regard to European Parliament representation, it is not possible to have a constituency for the European Parliament that is outside the European Union and only EU citizens can vote in European elections.

"That is in the treaties. It would not be possible to have a constituency of Northern Ireland. Even if it was possible, only EU and Irish citizens would be allowed to vote. One would have to forbid UK citizens from voting and that would be a problem."

The Taoiseach said Fine Gael's surprising decision to run former Foyle MP and SDLP leader Mark Durkan in Dublin in European elections in May would allow the people of Dublin to give the North and Ireland a voice in Europe.

He also suggested that in future it could be possible for the North to elect 'observers' to the EU in the same way as accession countries like Albania, Macedonia, Montenegro, Serbia and Turkey.

"In voting for Mr. Mark Durkan in the European elections people will have an opportunity to ensure there is somebody living in Derry who can represent all of the Ireland in the European Parliament.

"We will look at other mechanisms that might work. Accession countries can elect observers to the European Parliament and perhaps we might do something similar for Northern Ireland, but I cannot promise that at this stage," he said.