Michel Barnier, the European Union’s chief Brexit negotiator, meets Ireland’s Taoiseach Leo Varadkar at an all All-Island Civic Dialogue on Brexit in Dundalk, Ireland, April 30, 2018.

:: The European Commission’s chief Brexit negotiator Michel Barnier warned the talks were at “risk” because of disagreements over the future of the Irish border after Britain leaves the European Union.

At a press conference during his visit to Ireland, Barnier called for a “clear and operational solution for Ireland” to be included in the Brexit deal, adding: “Until we reach this agreement, there is a risk”.

Irish Prime Minister Leo Varadkar warned that Britain’s “approach to negotiations will need to change in some way” if there is to be agreement over the issue.

London has committed to avoid a “hard border” with checkpoints between British-ruled Northern Ireland and EU-member Ireland, which all sides agree is vital to maintaining the 1998 Good Friday peace accords.

However, it has also said it will not enter into a customs union with the EU post-Brexit, and has been urged to find a solution to reconcile the two positions.

The EU has suggested a “backstop” proposal, in which only Northern Ireland stays in a customs union with the EU post-Brexit, could be a possible solution.

“The backstop we put in the draft treaty, is not there to change the UK red lines, it is there because of the UK red lines, because of the red lines on the customs union and single market,” said Barnier.

Ireland foreign minister Simon Coveney said that “substantial progress” needed to be made by June’s European Council meeting.