Brussels has repeated its demand for the UK to abandon plans to override elements of the Brexit withdrawal treaty or face legal action.
It comes despite the Prime Minister agreeing a compromise with Tory rebels concerned about the controversial UK Internal Market Bill.
Boris Johnson agreed to table an amendment to the legislation giving MPs a vote before the government can use powers which would break international law and breach the deal brokered with the EU last year.
Meanwhile, Scottish secretary Alister Jack has insisted to MPs that passing the Bill into law “is the right thing to do”, even if the Scottish Parliament refuses to grant formal consent to it.
The Scottish and Welsh governments say the legislation steals powers from the devolved parliaments by giving Westminster the ability to lower standards and fund projects in devolved areas.
Much of the focus on the Bill has been on the breaches of international law within it, relating to the Northern Ireland protocol in the withdrawal agreement.
The Northern Ireland protocol is designed to maintain an open border with the Republic by keeping Belfast aligned with EU customs rules – amid fears border checks could spark paramilitary violence.
But provisions in the Internal Market Bill enable UK ministers to “disapply” rules on the movement of goods within the treaty if Britain is unable to strike a trade deal with Brussels before the transition period ends in January.
As well as angering scores of Conservative backbenchers, the proposals prompted the European Commission to threaten legal action if those specific provisions in the Bill are not removed by the end of the month.
And on Wednesday, Democratic US presidential election frontrunner Joe Biden insisted the Good Friday peace deal in Northern Ireland cannot become a “casualty” of Brexit.
Biden tweeted: “We can’t allow the Good Friday Agreement that brought peace to Northern Ireland to become a casualty of Brexit.
“Any trade deal between the US and UK must be contingent upon respect for the Agreement and preventing the return of a hard border. Period.”
In response, No 10 said the UK Government was working with US politicians to make sure people understood its position.
A spokesman said: “We continue to remain absolutely committed to no hard border and no border infrastructure between the Republic of Ireland and Northern Ireland.
“We will continue to engage with our US partners on a bipartisan basis to ensure that our positions are understood.”
It comes after Lord Keen, the advocate general for Scotland, resigned from Johnson’s government over the Bill, telling the PM he could not “reconcile what I consider to be my obligations as a law officer with your policy intentions”.
In an attempt to head off a Tory rebellion on the legislation, Downing Street reached a compromise with lead critic and ex-justice minister Sir Bob Neill on Wednesday night.
A government amendment would prevent ministers from activating powers in the Bill to override the Brexit divorce deal until MPs had voted to approve it first.
But despite this compromise, Brussels said on Thursday that its position had not changed and it still wanted the provisions to be withdrawn.
Eric Mamer, chief spokesman for the European Commission, told a press briefing: “We have as you know set out a position extremely clearly, it is in our statement, and it relates to those clauses being withdrawn from the law.
“That position has not changed and we have asked the UK to do this at the earliest possible convenience, and by the end of September at the latest.
“That has not changed.”
The spokesman also insisted the EU carries out negotiations in “good faith”, after the Prime Minister told MPs on Wednesday he did not believe they had done so in the ongoing trade talks.
Bill ‘is the right thing to do’
Elsewhere, at the Scottish Affairs Committee in Westminster on Thursday, the Scottish secretary denied the legislation was a “power grab” on Holyrood.
And despite being told it was “extremely likely” that Holyrood would not grant it legislative consent, Alister Jack indicated the UK Government would press ahead regardless.
The Sewel Convention, which has been in place since the Scottish Parliament was established, sets out that Westminster will “not normally” legislate in devolved areas without the express consent of those administrations, although it has done numerous times.
Jack said: “We are legislating because under the Sewel Convention there is this convention of not normal.
“This legislation is required because we are leaving the European Union – that was not, when the Scottish Parliament was established, something that was envisaged.
“So we now need to pass bills to secure the United Kingdom economy and secure the internal market… that is the right thing to do.”
First Minister Nicola Sturgeon previously branded the Bill an “abomination” that will “break” devolution.
But Jack insisted it would “strengthen the United Kingdom”, adding: “Not a single power is being taken away.
“All powers that the Scottish Government have now they will still have, and they will have over 100 more powers.
“The Scottish Parliament is the most powerful devolved parliament in the world and it is only about to get more powerful, there is no question that is the case.
“The idea that this is wrecking devolution is fanciful and it is fanciful more so when it comes from a party that wants to destroy it altogether and move to independence.”
Capital funding for schools and hospitals ‘at risk’
It came as finance ministers from the devolved administrations in Edinburgh, Belfast and Cardiff met on Thursday to voice their collective concerns about the Bill.
Scotland’s finance secretary Kate Forbes said the Bill would allow the UK Government to spend money directly in areas where power is devolved to Holyrood, without requiring the consent of Scottish ministers.
She said: “It puts at risk funding for a whole host of capital programmes – schools, hospitals and infrastructure.
“It reverses the devolution process and we will oppose any attempt to bypass the Scottish Parliament and Government, which are elected by the people of Scotland.”
The Bill passed its first Commons hurdle on Monday night, backed by 340 votes to 263 at stage one.