EU leader Michel lashes out at Britain over post-Brexit plan

European Union leader Charles Michel used the virtual pulpit of the U.N. General Assembly on Friday to lash out at Britain for its threats to renege on parts of the withdrawal treaty it signed with the EU and warned that the 27-nation bloc won't back down in the final weeks of acrimonious talks on a free-trade deal.

Michel made unmistakable references to the United Kingdom when he said that “respect for treaties, a basic principle of international law, comes to be considered optional even by those who, until recently, were its historical guarantors."

“All this in the name of partisan interests." he said in reference to the government of British Prime Minister Boris Johnson. The United Kingdom is a founding nation of the United Nations and a member of the Security Council, and the country has been a global diplomatic juggernaut for centuries.

Michel's ire was raised when Johnson said he would contemplate breaking an agreement he himself signed with the EU.

Johnson’s proposed a bill earlier this month that would disregard part of the Brexit withdrawal treaty dealing with trade between the EU's Ireland and the United Kingdom. The withdrawal agreement officially allowed the United Kingdom to leave the bloc last Jan. 31.

The EU insists the full withdrawal bill must be respected for fear that it otherwise might re-ignite tensions on the island of Ireland. Northern Ireland has special status in the withdrawal agreement because it is the only part of the U.K. that shares a land border with an EU country.

Britain and the EU jointly promised in the Brexit divorce agreement to ensure there are no customs posts or other obstacles on the Northern Ireland-Ireland border. The open border is key to the stability that underpins the 1998 peace settlement that ended decades of violence between Irish nationalists and British unionists.

At the same time, Michel also buttressed the position of the EU's chief negotiator, Michel Barnier, in his talks with the U.K. on a free trade deal by insisting the EU won't bend to unreasonable compromises.

The talks have stalled over several issues, and the EU insists the U.K.'s negotiating strategy is to to hold on to the privileges it had as a member of the bloc without having to carry the burdens of that membership. The U.K. is seeking far-reaching access to the wealthy EU market, but doesn't want to live by the rules that underpin trade with the bloc.

“Access to our large market — the second-largest economic zone in the world, and the first in terms of international trade — will no longer be sold off," Michel said. “From now on, we will better enforce the level playing field, in a market open to those who respect its standards. Whether they leave our Union or want to move closer to it."