Senior figures from EU member states have threatened a strong response to the UK's legislation.
German Chancellor Olaf Scholz yesterday hinted at trade measures against the UK, while the EU's chief negotiator, Maroš Šefčovič, said the European Commission could resume legal action against London.
Mr Šefčovič will brief members of the European Parliament later today.
Last night, one senior EU figure after another denounced the UK bill that would tear up the protocol.
Mr Scholz said the EU had its entire toolbox at its disposal, in other words, the EU could take retaliatory trade measures.
Senior Italian, Dutch and Austrian ministers all accused the UK of threatening to break international law.
The European Commission waited until the bill was laid before the House of Commons before responding.
Mr Šefčovič said the EU would not renegotiate the protocol.
More from RTE's report with business leaders sounding a note of caution.
