Brussels has warned it will launch legal action “very soon” following a move by the UK to unilaterally delay implementation of part of the Brexit deal relating to Northern Ireland.
European Commission vice president Maros Sefcovic said the announcement by Government on Wednesday had come as a “very negative surprise”.
The Cabinet Office Minister Lord Frost said the UK was extending a series of “grace periods” designed to ease trade between Northern Ireland – which remains in the EU single market for goods – and Great Britain while permanent arrangements are worked out.
It provoked a furious response in Brussels, with the EU accusing Britain of going back on its treaty obligations in the Brexit Withdrawal Agreement intended to ensure there is no return of a hard border between Northern Ireland and the Republic.
In an interview with the Financial Times, Mr Sefcovic – who is responsible for overseeing the implementation of the agreement – said the European Commission was now working on “infringement proceedings” against the UK.
“We are currently preparing it and it would be really something coming to our table very soon. The most precise term I can give you is really very soon,” he said.
His warning came after Boris Johnson had sought to play down the dispute, saying the Government was simply taking some “temporary and technical measures” to ensure that trade kept flowing.
“I’m sure with a bit of goodwill and common sense all these technical problems are eminently solvable,” he said on Thursday.
However MEPs in the European Parliament have already taken steps to delay formal ratification of the wider trade and co-operation agreement between Britain and the EU pending the outcome of the latest row.
The Northern Ireland protocol in the Withdrawal Agreement was designed by the EU and UK to avoid a hardening of the border on the island of Ireland.
It means keeping Northern Ireland aligned to various EU rules, requiring checks on goods arriving into the region from Great Britain.
Meanwhile the White House has again stressed the support of new US President Joe Biden for the Good Friday Agreement which the protocol is intended to protect.
Press secretary Jen Psaki said: “President Biden has been unequivocal about his support for the Good Friday Agreement.
“It has been the bedrock of peace, stability and prosperity for all the people of Northern Ireland.”
Prior to last year’s election, Mr Biden – who is intensely proud of his Irish roots – warned the agreement must not become a casualty of Brexit.