Moves to have the Irish Sea declared as the border after Brexit represent a hardening in attitude by the Irish government

Simon Coveney is pushing for the Irish Sea to become the post-Brexit border with the UK in a move that has ratcheted up tensions with the British government.

The minister for foreign affairs has told UK ministers that their idea of a “technical solution” to allow free trade to continue between the North and the South is unworkable. He has also said that Brexit risks endangering the Good Friday agreement.

His position has elicited a terse response from senior British officials.

“There is a new taoiseach and a new foreign minister and they’re stamping their authority,” a senior British government source told The Times. “We’re being as positive as we can but it’s true to say their attitude has hardened.”

Mr Coveney has called