Boris Johnson has been accused of aping Donald Trump's tactics in Brexit negotiations as ministers voiced defiance over breaking the terms of the divorce deal.
The PM is facing a furious Tory mutiny amid claims he is trashing the UK's moral authority by reneging on the Withdrawal Agreement, only signed in January.
Legislation due to be published today would unilaterally decide details that Brussels insists must be settled by a joint committee, including customs arrangements between mainland Britain and Northern Ireland.
Northern Ireland Secretary Brandon Lewis sparked outrage yesterday by bluntly admitting that the measures will breach international law.
But despite threats of 'consequences' from the EU, fellow Cabinet minister Matt Hancock insisted this morning that he is 'comfortable' with the move, because the government's 'primary' duty is to protect the Peace Process.
The UK's former ambassador to the US has waded into the row by suggesting that the dramatic step is a Trump-style bid to get a better deal in post-Brexit trade negotiations, which are at a critical stage.
Lord Darroch said he suspected Mr Johnson was trying to 'create chaos' so he could extract better terms, and there was an 'aspect of the way Donald Trump would have done it'.
Former UK ambassador Lord Darroch said he suspected Boris Johnson was trying to 'create chaos' so he could extract better terms, and there was an 'aspect of the way Donald Trump would have done it' (PM and US president are pictured together last September'
Health Secretary Matt Hancock insisted he was comfortable with the move in the circumstances, saying the government's 'primary' duty was to protect the Peace Process in Northern Ireland - which is also underpinned by a treaty
Michel Barnier arrived in London this morning as the EU and UK conduct a make or break round of negotiations on the future trade relationship
Boris Johnson, pictured in Whitehall yesterday, is due to hold a press conference later when he could be grilled about the situation
Michel Barnier's team made threats to make food exports from Great Britain to Northern Ireland illegal if the UK did not bow to their trade deal demands, it emerged today.
The chief negotiator's warning prompted the government to make legal changes to the Withdrawal Agreement, according to the Sun.
Under the deal, the export of products of animal origin, including meat, fish, shellfish, eggs and dairy from the UK mainland to Northern Ireland will be subject to EU oversight.
After Brussels warned the UK might not be on an approved list in the event of a No Deal, ministers demanded new domestic legislation in the Withdrawal Agreement, to avoid exports being made illegal.
There are claims that the move was sparked by a threat from EU negotiator Michel Barnier, who arrived in London this morning for make or break trade talks, to block food exports from Britain to the province unless the government capitulates in trade talks.
But anger in Brussels is rising at the situation, with European Parliament president David Sassoli warning of 'serious consequences' and MEPs raging that the idea of being 'half legal' is equivalent to being 'half pregnant'.
In a round of interviews this morning, Mr Hancock said: 'The government has a number of international obligations.
'The primary amongst those in this context is protecting the Peace Process. That is about safety and security too.'
Downing Street had previously sought to play down controversy over the Internal Market Bill legislation, which is being published today and will limit the role of the EU in Northern Ireland after Brexit.
It said 'limited clarifications' were needed to protect the Peace Process if talks on a trade deal break down.
However, the controversy escalated dramatically yesterday when Mr Lewis was asked directly whether the Government's proposals were illegal.
He replied: 'Yes, this does break international law in a very specific and limited way.'
Whitehall sources said there was 'strong precedent' for the UK occasionally breaching treaty obligations in exceptional circumstances, such as the refusal to give prisoners the vote.
But Mr Lewis's comments triggered a backlash led by former prime minister Theresa May and prompted warnings the move could undermine fragile hopes of a Brexit trade deal.
Earlier, the row prompted the resignation of Sir Jonathan Jones, head of the Government's legal department.
Sir Jonathan gave no public reason for his decision to quit, but a former colleague said: 'He is not someone who has ever wanted to push himself into the limelight. If he has done this, it demonstrates that he must see what they are doing as a terrible insult to the law.'
Last night there were rumours that Scotland's Advocate General, Lord Keen, was also considering quitting.
The Attorney General's office confirmed that its director general, Rowena Collins Rice, was leaving, but insisted it was unrelated.
Attorney General Suella Braverman and Justice Secretary Robert Buckland also faced calls to quit. But sources said both ministers would stay.
Asked by Times Radio if he was comfortable with a minister saying the UK was willing to break international law, Mr Hancock replied: 'I am.'
He said: 'The primary international obligation around this issue is to protect the peace process in Northern Ireland and I very much hope we conclude a deal before the end of the transition period.
'I think that we will and it is in everybody's interest to do so as we did last time, but I also understand why ministers have chosen to prioritise at the absolute top of that the importance of protecting the peace process in Northern Ireland.'
Foreign Affairs Committee chair Tom Tugendhat warned that the action could undermine the UK's moral authority in its dealing with countries like China.
The UK's former ambassador to Washington has said he wonders if there is an 'aspect of the way Donald Trump would have done it' about Boris Johnson's handling of Brexit talks.
Lord (Kim) Darroch referred to comments made by Mr Johnson in 2018, in which he reportedly said there would be 'all sorts of chaos' at the start of Brexit negotiations if Mr Trump were in charge.
Speaking to BBC Two's Newsnight, Lord Darroch said: 'If you go back to the Prime Minister's sayings back in 2018, he said – and this was picked up at the time at a private sort of gathering once: 'If Donald Trump was negotiating Brexit, he would create chaos right at the start of negotiations. And, you know, all sorts of, you know, people would be outraged by what he was saying and demanding and there'd be huge rows. And then he might get a very good outcome. And we should, we should, we should think about that'.
'That was when he was becoming increasingly dissatisfied with the then track of the Brexit negotiations.
'And now as I watch him and the Government conduct the post withdrawal future relationship arrangements, I just wonder if there's an aspect of the way Donald Trump would have done it and how he is doing it.'
Lord Darroch was forced to stand down last year after diplomatic cables he wrote criticising the Trump White House as 'inept' and 'dysfunctional' were leaked to the press.
'The UK has been the chief exporter of the rule of law,' he told an event organised by the British Foreign Policy Group last night.
'We have been the single pillar of dependability in international negotiations… which has allowed others to prosper and indeed allowed us to prosper.
'It's not just about the law. Our entire economy is based on the perception that people have of the UK's adherence to the rule of law...
'What we actually need to do is to stick to (the rule of law), and expand that, if we are to deal with China.'
Another senior Tory MP joined the backlash this morning, saying breaching international law would 'go against everything we believe in'.
Chairman of the Commons defence committee Tobias Ellwood told BBC Radio 4's Today programme: 'As negotiations go down to the wire let's not lose sight of who we are and what we stand for.
'This is about the rule of law and our resolve and commitment to uphold it. To unilaterally ignore any treaty in its obligations which we've signed and submitted to the United Nations would actually go against everything we believe in.'
Whitehall sources have