'Patience wearing thin': EU threatens UK with tariffs over implementation of Northern Ireland Protocol

He warned that the EU could impose tariffs on British goods. Northern Ireland has so far remained in the bloc's customs unions as part of the Brexit treaty agreed in December 2020.

It has also remained so in order to avoid the creation of a physical border between the Republic of Ireland and Northern Ireland which many fear could spark sectarian violence on the island once more.

A border has been effectively created in the Irish sea between Great Britain and Northern Ireland as certain goods now need to be checked before travelling across the sea, Euronews reported.

UK Prime Minister Boris Johnson, who negotiated the Withdrawal Agreement now in force, has since called it "ludicrous". A grace period was initially agreed with London unilaterally decided earlier this year to waive checks.

The grace period allowed under the agreement of the protocol is set to expire on June 30 but Britain now wants to extend that waiver to 2023, which has been rejected by the EU.

Sefcovic also told reporters that "EU has engaged creatively and tireless to find solutions" over the Northern Ireland Protocol and agreed to an initial grace period for border checks "because the UK was not technically ready to implement" it.

He said that the EU has demonstrated "a very constructive approach and enormous patience" but that the latter is now "wearing very, very thin", reported Euronews.

The bloc had already launched legal action against London over its decision to unilaterally extend the initial grace period. It has now threatened legal action, which would include arbitration and "cross retaliation".