The European Commission has started legal proceedings against Britain over what it says are a breach of its obligations under the Northern Ireland Protocol.
The commission says it has sent a letter of formal notice to the United Kingdom for breaching "substantive provisions of the Protocol on Ireland and Northern Ireland" - as well as the good faith obligation under the Brexit Withdrawal Agreement.
It notes this is the second time in six months that the UK government is set to breach international law.
As well as the formal notice, the EU is calling on the UK government to "rectify and refrain from putting into practice" its unilateral measures.
Foreign Affairs Minister Simon Coveney has said the EU was left with 'no alternative'.
Legal Action is not a welcome development, but approach of UK Govt has given EU no alternative. Unilaterally changing how Protocol is implemented is breach of Agreement.
We need to get back to UK/EU cooperation, working with business in NI & focused on solving problems together. https://t.co/WrWTQKAUpy
— Simon Coveney (@simoncoveney) March 15, 2021
In a tweet, he said: "Legal action is not a welcome development, but approach of UK Govt has given EU no alternative.
"Unilaterally changing how Protocol is implemented is breach of Agreement.
"We need to get back to UK/EU cooperation, working with business in NI & focused on solving problems together."
What happens now?
The UK now has one month to submit its observations to the letter of formal notice.
After this, the commission could ask the European Union Court of Justice to take action - including the possibility to impose a lump sum or penalty payment.
If the UK fails to enter into consultations in good faith, with the aim of reaching a mutually agreed solution by the end of this month, the EU may provide written notice to commence consultations "as a first step in the Dispute Settlement Mechanism process" of the Brexit Withdrawal Agreement.
If no solution is found, the EU could refer the dispute to binding arbitration - which could also result in financial sanctions.
If this were to happen and there was a case of non-payment or persisting non-compliance, the EU could "suspend its obligations under the Withdrawal Agreement" - or impose tariffs on imports of goods from the UK.
Grace period for Northern Ireland
This comes almost two weeks after London announced plans to unilaterally extend a grace period for food imports from Britain into Northern Ireland.
It means businesses exporting food from Britain to Northern Ireland will not have to provide the necessary paperwork for a further six months.
However, the EU warned that the move breached the Northern Ireland Protocol, and questioned why it was taken without any discussion with Brussels.
It said: "The UK resorted to this unilateral action without any discussion or consultation with the EU side in the bodies established by the Withdrawal Agreement.
"It constitutes a clear departure from the constructive approach that had prevailed up until this point, thereby undermining both the work of the Joint Committee and the mutual trust and spirit of cooperation that had been rebuilt in the final months of 2020, after the uncertainty created by the UK Internal Market Bill."
Minister of State for European Affairs Thomas Byrne said it was "quite simply dangerous" for the UK to take any unilateral actions on the protocol.
"When one side takes unilateral action – and we have seen this a number of times now since last summer – that creates huge difficulties for the peace process and that is what we don’t want to happen," he said at the time.
While Northern Ireland DUP MP Jeffrey Donaldson has previously suggested the British government did not change the protocol by extending its grace period.
He claimed: "The UK is not changing the Northern Ireland Protocol, they're simply extending the grace period before the protocol is implemented in full.
"Would that the UK were changing the protocol, I would quite welcome that.
"But they're not, so let's not turn this into something it isn't".
He also denied that the UK was changing the terms of the deal.
"The UK government has the right to apply this grace period, the EU agreed to it, the UK sought an extension to that, the Irish Government is supporting that extension".
"To date, the EU has not agreed the extension, so the UK government - in the interest of giving businesses some degree of certainty - has taken action to extend the grace period".