Nine months after Boris Johnson won a smashing majority on the promise of an "oven-ready" Brexit deal, the U.K. government is threatening to blow up trade talks with the European Union by declaring its intent to violate that very agreement.

Driving the news: An emergency U.K.-EU meeting was called in London today after a government minister made a stunning admission on the floor of the House of Commons this week — that a new bill seeking to override parts of the Brexit deal would indeed "break international law."

How we got here: The three-year political deadlock that followed the 2016 Brexit referendum effectively boiled down to one thorny issue — how to extricate the U.K. from Europe's customs rules while avoiding a hard border between Northern Ireland and the Republic of Ireland.

• The elimination of border controls was a central plank of the Good Friday Agreement, which brought an end to decades of sectarian violence in Northern Ireland. The U.K. and the EU have consistently expressed their commitment to upholding the peace deal.
• Johnson managed to strike an unlikely Brexit deal by agreeing to keep Northern Ireland aligned with EU rules, effectively creating a customs and regulatory border in the Irish Sea.
• A joint EU-U.K. committee would be established to determine whether goods traveling to Northern Ireland from England, Scotland and Wales would be "at risk" of entering the Republic, and therefore subject to EU customs checks.

Flash forward: Johnson succeeded in ramming the deal through Parliament on an expedited timetable, allowing the U.K. to leave the EU on Jan. 31 and buying him an 11-month transition period to negotiate a comprehensive free-trade agreement.

• Those talks have faltered. Johnson is now threatening to walk away from the table on Oct. 15 so the country can prepare for a "no-deal" Brexit on New Year's Eve.
• The surprise bill introduced this week would allow U.K. ministers to unilaterally determine which goods should be subject to EU checks and tariffs when passing from Great Britain to Northern Ireland.
• In other words, with negotiations at risk of collapsing, the government is reneging on an international treaty that Johnson himself signed, stamped and delivered.

The view from Downing Street: The Brexit deal isn't "like any other treaty," a government spokesperson said in a statement, stressing that it was always written on the basis that the U.K. and EU would work through some of its ambiguities.

• "It was agreed at pace at the most challenging political circumstances, to deliver on a clear political decision of the British people," the spokesperson added.

The view from Westminster: It's not clear what kind of parliamentary rebellion Johnson's bill is facing, but three former leaders of his own Conservative Party — John Major, Michael Howard and Theresa May — have excoriated the move.

• "How can we reproach Russia, or China, or Iran when their conduct falls below internationally accepted standards, when we are showing such scant regard for our treaty obligations?" Howard asked today.

The view from Brussels: The EU has urged the U.K. to scrap the bill and is threatening legal action if it refuses.

• The U.K. has "seriously damaged trust" between the two sides, the European Commission said in a statement. "It is now up to the U.K. government to re-establish that trust."

The view from Washington: The prospect of a lucrative trade deal with the U.S. has always been touted as one of the main arguments for Brexit. But according to House Speaker Nancy Pelosi, there is "absolutely no chance" of Congress passing a deal if the U.K. violates the Good Friday Agreement.

The bottom line: Experts have longwarned about the potentially catastrophic economic disruptions that could result from a "no-deal" divorce from the EU, the U.K's largest and closest trading partner.

• The likelihood of that happening is now higher than it ever was during three years of pre-Brexit stalemate — this time with an economy already devastated by the coronavirus.

Go deeper: Northern Ireland's Brexit balancing act (2019)