Ed Miliband accused Boris Johnson of seeking to “get Brexit undone” during a widely-praised speech against the controversial UK Internal Market Bill.
The former Labour leader-turned shadow business secretary warned MPs that passing the legislation would “equip the government with the power to break the law” and was a matter of “right versus wrong” rather than “Leave versus Remain”.
He variously accused Mr Johnson of incompetence, “legislative hooliganism” and seeking to blame others for his own Brexit ‘mess’.
Mr Miliband said: “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.
“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.”
Mr Miliband 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.”
The Labour MP went on to say that the Internal Market Bill, which has been criticised by former prime ministers Theresa May, David Cameron, Gordon Brown, Tony Blair and John Major, was “trashing” the UK’s reputation around the world.
Mr Miliband joked: “The PM has said he wants to bring unity to the country … I therefore congratulate him on having in one short year united his five predecessors.”
In a reference to the Northern Ireland secretary Brandon Lewis’ admission that the bill broke international law, Mr Miliband suggested the government wanted to create the “Johnson defence”, explaining: “You can break the law in a specific and limited way.”
And in a swipe at Mr Johnson’s election slogan, Mr Miliband added: “From a man who says he wanted to get Brexit done and won an election on it, this bill gets Brexit undone.”
Commentators on social media quickly described the speech as a “humiliation” and an “annihilation” of Mr Johnson in front of his own MPs.
Others pointed out the prime minister’s facial expression at one point during the speech, or criticised the prime minister’s decision to spend part of it looking at his mobile phone while Mr Miliband continued speaking.
The bill eventually passed its second reading by 340 votes to 263, after most Tory rebels abstained rather than voted against it.
Mr Johnson had opened the debate by insisting the Bill is “essential for guaranteeing the economic and political integrity of the United Kingdom”.
After accusing the EU of “holding out the possibility of blockading food and agriculture transports within our own country”, he said: “Let us seize the opportunity presented by this Bill and send a message of unity and resolve. Let’s say together to our European friends that we want a great future relationship and a fantastic free trade deal.”
Additional reporting by Press Association
