The European Union is considering legal action against the UK after Boris Johnson pressed ahead with plans to override parts of the Withdrawal Agreement.
The bloc believes it may be able to mount a challenge before the Government manages to pass legislation which changes part of the deal struck last year relating to Northern Ireland, which ministers admit does breach international law in a "very specific and limited way."
According to Bloomberg, a draft working paper prepared by Brussels and circulated to member states warns that the UK Internal Market Bill represents a “clear breach” of the agreement which would “open the way to legal remedies”.
It adds that once the transition period ends, the EU could also trigger the dispute settlement mechanism contained in the deal, which could ultimately result in the UK being hit with financial sanctions.
It came as the EU called for emergency talks to salvage the Brexit negotiations. The talks will take place on Thursday.
Eric Mamer, chief spokesman of the EU Commission, said on Twitter: “The EU seeks clarifications from the UK on the full and timely implementation of the Withdrawal Agreement.”
Maros Sefcovic, Michael Gove’s counterpart on the UK-EU joint committee set up to implement Brexit, said he would hold an extraordinary meeting as soon as possible to address the bloc’s “strong concerns.” That meeting will go ahead on Thursday.
Mr Sefcovic told reporters: “The Withdrawal Agreement is not open for renegotiation and we expect the letter and the spirit of the Withdrawal Agreement will be fully respected. I think on that we have to be very, very clear."
It came as Ursula von der Leyen, the European Commission President, said she was “very concerned”after the Government published the Internal Market Bill, which she warned “breaks international law and undermines trust.”
On Wednesday, Number 10 issued a fresh line of defence, telling reporters that the withdrawal agreement had been signed "at pace" and it had always been intended that grey areas in the treaty could be clarified later on.
However, Ms von der Leyen said the legal principle of pacta sunt servanda - that an agreement cannot be reneged on - was the “foundation of prosperous future relations”.
Charles Michel, the president of the European Council added that the “breaking international law will not create the confidence we need to build our future relationship”.
Michel Barnier, the EU’s chief negotiator, arrived in London yesterday, with sources indicating he would confront his opposite number Lord Frost over the UK’s proposals to change parts of the deal relating to Northern Ireland.
Ahead of the meeting, an EU diplomat told The Telegraph: “A quick reading of the relevant articles of the Internal Market Bill suggest the UK Government is launching a frontal assault on the Protocol and its obligations.
“Notwithstanding the consequences for the negotiations this must be the absolute nadir of four years of negotiations by a country known as the cradle of democracy.”
However, a second EU official insisted the bloc would not walk away at this point, adding that Mr Barnier would frame the UK as being the party responsible for this mess.”
Responding yesterday, a Government spokesman said they welcomed Mr Sefcovic's request for an additional meeting of the joint committee and would be looking to agree a date with his team.
British officials will tell their EU counterparts they do not intend to walk away from any commitments or explicit promises made in the joint committee, The Telegraph understands.
Mr Johnson faced further criticism at homeon Wednesday as Sir John Major became the second former prime minister after Theresa May to warn that changing the withdrawal agreement risked undermining trust in the UK and its standing internationally.
“For generations...our signature on any treaty or agreement has been sacrosanct,” he added. "If we lose our reputation for honouring the promises we make, we will have lost something beyond price that may never be regained."
Meanwhile, in Washington, senior Democrats warned the UK risked jeopardising a US trade deal if it failed to uphold the withdrawal agreement.
They included Richard Neal, the head of the House of Representatives’ ways and means committee, which holds significant sway over the signing of US trade deals.
Mr Neal claimed that Joe Biden, the Democratic presidential candidate, who is leading Donald Trump in the polls, “shares my position”, adding any move which risked a hard border on the island of Ireland represented a “very significant problem.”
Mr Biden, an Irish American, is a strong supporter of the Good Friday Agreement, which requires an open border and of which the US is the guarantor.
His comments were echoed by Nancy Pelosi, the most senior Democrat in the House of Representatives, who told the Irish Times: “If the UK violates that international treaty and Brexit undermines the Good Friday accord, there will be absolutely no chance of a US-UK trade agreement passing the Congress."
Both the House, in which the Democrats wield a majority, and the Senate, will need to ratify any trade deal with the UK.
However, the Prime Minister’s spokesman insisted that protecting the Northern Ireland peace process was “exactly” why the UK was making the changes.
“We are absolutely committed to no hard border between Northern Ireland and the Republic of Ireland,” he added.
Speaking earlier at Prime Minister’s Questions, Mr Johnson said: “We need a legal safety net to protect our country against extreme or irrational interpretations of the protocol which could lead to a border down the Irish Sea which I believe...would be prejudicial to the interests of the Good Friday Agreement and prejudicial to the interests of peace in our country.”