Britain’s divorce from the European Union must not disrupt trade across the Ireland-Northern Ireland border. This is what the leader of Britain’s main opposition Labour Party, Jeremy Corbyn, said he told the EU’s Brexit chief Michel Barnier in talks on September 27.

Corbyn said he was laying out Labour’s views on the dangers of a no-deal Brexit. “He (Barnier) was interested to know what our views are,” Corbyn told reporters.

As reported by the Reuters news agency, Barnier has offered no opinion on the merits of Labour’s Brexit proposals, which envisage Britain staying in a customs union with the EU after Brexit. This is in opposition to proposals tabled by British Prime Minister Theresa May.

On September 26, Corbyn said Labour would vote against a Brexit deal based on May’s own proposals, the strongest warning yet to a prime minister whose plan to leave the EU is hanging by a thread.

According to Reuters, May has said the EU needs to show Britain respect and come up with their own alternatives to her so-called “Chequers” proposals, which EU leaders rejected at a summit in Austria last week. She has said Labour’s meetings with EU officials are undermining her efforts to negotiate a Brexit deal.