Brexit withdrawal deal must be implemented 'with rigor' -EU's Barnier

The European Union will monitor the Northern Ireland elements of Britain's Brexit agreement very closely and will not allow London to re-open the deal "under the guise of implementation," the EU's chief Brexit negotiator said on Monday.

"The withdrawal agreement must be applied with rigor and discipline by all sides. It cannot be re-opened under the guise of implementation," Michel Barnier told an audience at Queen's University Belfast.

"We will be monitoring its correct application very carefully," he added.