Former prime minister theresa may denounced the governments internal market bill on monday night, arguing that it would cause untold damage to britains standing in the world.
The bill, which would allow the uk to override parts of the eu withdrawal agreement relating to northern ireland, has caused consternation even within the tory party and been strongly criticised by both brussels and the us presidential candidate joe biden.
Speaking in the house of commons, mrs may accused the government of acting recklessly and irresponsibly and said she could not support the legislation.
I cannot emphasise how concerned i am that a conservative government is willing to go back on its word, to break an international agreement signed in good faith and to break international law.
Mrs may added: this will lead to untold damage to the united kingdoms reputation, it puts the future of the united kingdom at risk and, as a result, with regret, i have to tell the minister i cannot support this bill.
The bill is designed to grant ministers powers to override key aspects of the withdrawal agreement including the northern ireland protocol, with respect to state-aid rules and customs declarations.
Earlier this month, northern ireland secretary brandon lewis conceded that the bill would break international law in a very specific and limited way, while justice secretary robert buckland argued that it was merely an insurance policy.
The internal market bill has since been met with fierce opposition from several political heavyweights, including former attorney-general geoffrey cox and former conservative leader michael howard.
In a joint piece in the sunday times, former prime ministers tony blair and john major described the legislation as shameful, adding: this way of negotiating, with reason cast aside in pursuit of ideology and cavalier bombast posing as serious diplomacy, is irresponsible, wrong in principle and dangerous in practice.
On monday last week, mps in the house of commons backed the second reading of the bill by 340 votes to 263.
However, two conservative mps voted against the legislation, while more than 20 mps abstained, including charles walker, who said parliament needed to exhaust all other options.
He added: im not going to be voting for this bill at second reading because if you keep whacking a dog, dont be surprised when it bites you back.
Amid fears of a tory rebellion led by mp bob neill, mr johnson offered mps concessions on wednesday, agreeing a parliamentary lock where members would have a vote on any further action on the key clauses.
But in a closed-door briefing on friday, european commission officials and eu in-house lawyers claimed that the compromise reached by mr johnson did little to address concerns of the eu and still breached international law.
Amid the growing unease with the implications of the bill, a flurry of high-profile figures have resigned in recent weeks.
On september 8, jonathan jones, the treasury solicitor and permanent secretary at the government legal department, resigned from his position.
Individuals close to sir jonathan suggested that he had become very unhappy over government proposals to override parts of the northern ireland protocol.
His resignation was followed by richardkeen, advocate-general for scotland, who argued that it had become increasingly difficult to reconcile his obligations as a lawyer with the intentions of the government.
On friday, amal clooney resigned from her position as the uks special envoy on media freedom in protest at the legislation.
In her letter addressed to foreign secretary dominic raab, ms clooney said that it was lamentable for the uk to be voicing its intention to violate an international treaty.