The shadow business secretary, standing in for Labour leader Sir Keir Starmer, warned MPs that passing the UK Internal Market Bill would “equip the Government with the power to break the law”.
He said Mr Johnson’s “cavalier” attitude must be opposed and the debate was not an argument about “Leave vs Remain” but “right vs wrong”.
The bill seeks to override the Brexit divorce deal, thereby breaching international law, in a bid to protect the relationship between Great Britain and Northern Ireland.
It also sets out the way that trade within the UK will work once outside the EU’s single market and customs union, amid concerns in Westminster that Brussels could seek to disrupt food goods travelling from Britain to Northern Ireland as part of trade talks.
Labour’s amendment to block the Bill at second reading was selected by Speaker Sir Lindsay Hoyle for consideration.
Speaking for the Opposition during the debate on Monday evening, Mr Miliband accused Mr Johnson of “legislative hooliganism” and said he had ignored warnings over how the Northern Ireland Protocol works and the mediation measures in place.
“Let’s just get this straight for a minute, because I think it is important to take a step back, what the Prime Minister is coming to the House to tell us today is that his flagship achievement, the deal he told us was a triumph, the deal he said, as I said, was oven ready, the deal (on) which he fought and won the general election is now contradictory and ambiguous,” he told the Commons.
“What incompetence. What failure of governance. And how dare he try and blame everyone else.
“Can I say to the Prime Minister, this time he can’t blame (Theresa May), he can’t blame John Major, he can’t blame the judges, he can’t blame the civil servants, he can’t sack the Cabinet secretary again.
“There’s only one person responsible for it, and that is him. This is his deal, it’s his mess, it’s his failure.”
He continued: “For the first time in his life, it is time to take responsibility, it is time to fess up.
“Either he wasn’t straight with the country about the deal in the first place or he didn’t understand it.
“Because a competent government would never have entered into a binding agreement with provisions it could not live with.
“And if such a government somehow missed the point but woke up later, it would have done what any competent business would do after it realised it can’t live with the terms of a contract, it would negotiate a way out in good faith.
“And that’s why this is all so unnecessary – because there is a mechanism designed for exactly this purpose in the agreement, the Joint Committee on the Northern Ireland Protocol.”
He also said the Government wants to create the “Johnson defence”, explaining: “You can break the law in a specific and limited way.”
Mr Miliband highlighted Home Secretary Priti Patel’s call for people to follow new Covid-19 laws, adding: “The Johnson defence means something very specific – there is one rule for the British public and another rule for this Government.
“Pioneered by Cummings, implemented by Johnson, that is the Johnson rule.”
The shadow business secretary concluded: “This is a pivotal moment in determining the future of our country – who we are and how we operate.”
Mr Johnson opened the debate by insisting the bill is “essential for guaranteeing the economic and political integrity of the United Kingdom”.
He insisted the legislation was a necessary “legal safety net” to protect the relationship between Great Britain and Northern Ireland.
“I regret to have to tell the House that in recent months the EU has suggested that it is willing to go to extreme and unreasonable lengths using the Northern Ireland Protocol in a way that goes well beyond common sense simply to exert leverage against the UK in our negotiations for a free trade agreement,” he said.
“To take the most glaring example, the EU has said that if we fail to reach an agreement to their satisfaction, they might very well refuse to list the UK’s food and agricultural products for sale anywhere in the EU.
“And it gets even worse. Because under this protocol that decision would create an instant and automatic prohibition on the transfer of our animal products from Great Britain to Northern Ireland.
“Our interlocutors on the other side are holding out the possibility of blockading food and agriculture transports within our own country.”
The Prime Minister added the EU has yet to take “that revolver” off the table.
“Let us seize the opportunity presented by this bill and send a message of unity and resolve,” he said.
“Let’s say together to our European friends that we want a great future relationship and a fantastic free trade deal.”
But all the living former prime ministers have voiced concern over the potential breach of international law, while ex-attorney general Geoffrey Cox and former chancellor Sajid Javid have added to high-profile Conservative criticism of the measure.
David Cameron said he had “misgivings” as “passing an Act of Parliament and then going on to break an international treaty obligation is the very, very last thing you should contemplate”.
Former chancellor Sajid Javid said he would not back the Bill at its second reading on Monday night.
“Breaking international law is a step that should never be taken lightly,” he said.
“Having carefully studied the UK Internal Market Bill, it is not clear to me why it is necessary to do so.”
Geoffrey Cox, Mr Johnson’s former attorney general when the Withdrawal Agreement was signed, said breaking international law would damage the UK’s standing.
“The breaking of the law leads ultimately to very long-term and permanent damage to this country’s reputation and it is also a question of honour to me – we signed up, we knew what we were signing,” he told Times Radio.