Pro EU protesters stand near Parliament in London, Monday, Sept. 14, 2020. Boris Johnson is facing the possibility of a Tory rebellion and major damage to his chances of a trade deal with the EU unless he removes controversial parts of the internal Bill which is in the House of Commons for its second reading Monday. (AP Photo/Frank Augstein)

LONDON - British Prime Minister Boris Johnson on Monday defended his plan to unilaterally rewrite Britain’s divorce deal with the European Union as an insurance policy against the bloc's unreasonable behaviour. The comments came as his former attorney general joined a growing number of once-loyal lawmakers condemning the contentious move.

Johnson said a planned law designed to override portions of the Brexit withdrawal agreement was needed because the EU might “go to extreme and unreasonable lengths” in its treatment of former member Britain.

“I have absolutely no desire to use these measures,” Johnson told lawmakers as he introduced the Internal Market Bill in the House of Commons. “They are an insurance policy.”

Johnson's Conservative government has acknowledged that the bill breaches the legally binding withdrawal treaty that Britain and the EU have both ratified. The legislation threatens to sink the already-foundering negotiations between Britain and the EU on a post-Brexit trade deal.

The U.K. formally left the bloc on Jan. 31, but existing trade rules remain in effect until the end of this year under a transition designed to provide time to negotiate a long-term trade agreement.

Ed Milliband, business spokesman for the opposition Labour Party, accused Johnson of “trashing the reputation of this country and trashing the reputation of his office.”

With an 80-seat majority in the House of Commons, Johnson is expected to have enough votes to push his legislation through Parliament despite opposition anger. But there is wide unease within the Conservative Party about the law-breaking move.

Geoffrey Cox, who was the government’s top legal officer when Johnson negotiated the Brexit withdrawal agreement less than a year ago, said reneging on the deal would be an “unconscionable” breach of international law.

“I simply cannot approve or endorse a situation in which we go back on our word, given solemnly,” Cox, previously a strong supporter of Johnson on Brexit, told Times Radio. “The breaking of the law ultimately leads to very long-term and permanent damage to this country’s reputation.”

Sajid Javid, a former Treasury chief in Johnson's government, also said he would not vote for the bill, because “I cannot support the U.K. pre-emptively reneging” on the withdrawal agreement.

As part of the Brexit divorce deal, Britain and the EU agreed to keep Northern Ireland — the only part of the U.K. to share a border with the bloc — bound to some EU rules on trade, to avoid the need for border checks on goods moving between Northern Ireland and the Republic of Ireland. Both sides accepted the compromise to protect the open border, which helps underpin the peace process in Northern Ireland.

The Internal Market Bill would give the British government the power to override the EU’s agreed role in oversight of trade between Northern Ireland and the rest of the U.K.

Johnson claims the EU has threatened to use “an extreme interpretation” of the withdrawal agreement to “blockade” food shipments from the rest of the U.K. to Northern Ireland unless Britain agrees to accept EU regulations.

He said the bloc was “threatening to carve tariff borders across our own country and to divide our own land.”

The EU denies threatening a blockade and says it merely wants Britain to live up to the terms of the agreement. EU leaders are outraged at the prime minister’s proposal and have threatened the U.K. with legal action if it does not drop the proposal by the end of the month.

Two former Conservative U.K. prime ministers, John Major and Theresa May, have condemned the legislation. On Monday a third, David Cameron, said he had “misgivings.”

Conservative lawmaker Rehman Chishti quite as the prime minister’s special envoy on freedom of religion in protest over the bill. He tweeted Monday that as a former lawyer, “values of respecting rule of law & honouring one’s word are dear to me.”

What mystifies some observers is that Johnson is repudiating a treaty that he himself negotiated and hailed as an “oven-ready” deal that would “get Brexit done.” That declaration of victory was key to Johnson's successful December 2019 election campaign.

“There was a political imperative on the government to get an agreement and then to go to the electorate with the claim that they had, to coin a phrase, got Brexit done,” said Tim Bale, professor of politics at Queen Mary University of London.

“I think it possibly was the case in some senses that it was ‘make the agreement in haste and then repent at leisure.’ And what we’re seeing now is the repentance.”

Johnson's move has dynamited he dwindling trust between Britain and the EU as they try to negotiate a new trading relationship.

Talks are due to continue this week in Brussels despite the chill in relations. Both sides say any deal must be agreed by next month so there is time for it to be ratified by Dec. 31.

If there is no deal, tariffs and other impediments to trade will be imposed by both sides at the start of 2021.

That would mean huge economic disruption for the U.K., which does half its trade with the bloc. A no-deal exit on Jan. 1 would also hit some EU nations, including Ireland, France, Belgium and the Netherlands, especially hard.

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