Mr Lammy was speaking at the UK in a Changing Europe conference when he conceded that Labour would not attempt to re-join the EU or the single market if elected into power. He did, however, take aim at potential changes to the Northern Ireland Protocol proposed by the Government.
The Northern Ireland Protocol Bill would see the UK unilaterally change parts of the deal to bring Northern Ireland back into the fold and prevent trade bottlenecks caused by EU checks within the UK’s borders.
Mr Lammy said: “Boris Johnson Conservatives are stuck in a fevered dream of 2016…picking petty fights with our closest allies instead of moving on and negotiating solutions.”
He added: “The only people this deal satisfies is the ERG.”
The European Research Group (ERG) is an influential group of Conservative MPs in Parliament who focus on the UK’s withdrawal from the EU.
He added: “This protocol bill is a charter for lawlessness that serves the interest of those who want to weaken the rule of law.
“One of the most troubling aspects of all of this is the dangerous legal distortion that’s used to justify it.”
Mr Lammy went on to claim the UK will be losing £100billion a year because of Brexit.
He said: “The Office of Budget Responsibility still predicts that the Government’s badly negotiated deal will reduce the United Kingdom’s gross domestic product by a staggering 4 percent. That’s 100 billion a year in lost output.”
The EU has claimed that the new Bill breaches international law while the Government says it is necessary to protect the Good Friday Agreement and bring Northern Ireland back in line with the rest of the UK.
READ MORE: Nigel Farage outlines three steps needed for UK to ‘get proper Brexit’
He also lambasted Lord Frost’s trade deal with Europe, claiming that, because of the deal, the UK would have the worst trade recovery in the G20 apart from Russia.
He said: “The Office of Budget Responsibility still predicts that the Government’s badly negotiated deal will reduce the United Kingdom’s gross domestic product by a staggering four per cent. That’s 100 billion a year in lost output.”
The comments come just hours after Lord Frost told the same conference that anyone who said that Brexit had negatively impacted trade and the economy had “an axe to grind”.
He claimed that the figures used to predict a four per cent decline were “zombie figures” based on studies of previous communist countries.
He said: “Those studies primarily looked at the effect of opening up badly run ex-communist and ex-authoritarian autarchic economies in which opening up was producing huge improvements to the policy regime more generally, and in which the gains came from these broader improvements not just from trade.”
Ukraine: Zelensky hits jackpot with new fighter jet deal [LIVE]
James Martin shares ‘crazy’ habit keeping us from losing weight [INSIGHT]
Queen’s go-to takeaway she enjoys when in Balmoral [REPORT]
Mr Lammy did tell the conference that Labour had no intention of re-joining the EU. He said he had “scars on his back” from trying to push a second referendum.
He said: “We are not going into the next election saying that we will enter the single market or the EU.
“You might not like it but Labour is determined to govern the entire country.”
He added: “We’re not going over it again. And I’m afraid, psychologically, we’ve got to come to terms with that.”