Theresa May will meet top EU official Donald Tusk on Thursday, 24 hours before a major speech on British relations with the bloc after Brexit.
Her talks with the European Council president come amid tensions over the EU’s draft withdrawal treaty.
Mrs May has said the EU’s proposals on Northern Ireland threaten the UK’s constitutional integrity.
The EU says the UK needs to come up a workable alternative to their proposals – which it describes as a “backstop”.
Mrs May, due to chair a meeting of the cabinet before her talks with Mr Tusk, has already pledged not to accept the draft treaty as it stands.
The treaty proposes a “common regulatory area” after Brexit on the island of Ireland – in effect keeping Northern Ireland in a customs union – if no other solution is found.
Both the EU and the Irish government say it is up to the UK to come up with concrete alternatives to what they describe as a “backstop” option.
Mrs May has said “no UK prime minister” could ever agree to a proposal that would create a customs and regulatory border in the Irish Sea and that she would make that “crystal clear” to EU officials.
Speaking on the BBC’s Newsnight programme, veteran Eurosceptic Sir Bill Cash said there were “technical ways” of managing the Irish border and accused the EU of trying to create a “constitutional crisis” for the UK.
Cabinet ministers have suggested Friday’s speech will give the EU the clarity that it has been seeking about what kind of trade relationship the UK wants after its departure on 29 March 2019.
In an apparent concession to the EU ahead of the speech, the government said EU nationals coming to the UK during a transition period after Brexit, expected to last two years, would get indefinite leave to remain.
Mrs May has said her long-term goal is a “bespoke economic partnership”, underpinned by a comprehensive free trade agreement guaranteeing tariff-free access to EU markets for British goods and services.
But her predecessor Sir John Major warned on Tuesday that an “a la carte entrance” to the European market was not possible if the UK left the single market and customs union – which Mrs May is committed to doing.
Losing existing trade advantages, he said, would make the UK a less attractive place for inward investment and could put 125,000 jobs at Japanese firms at risk.
Conservative Brexiteers have criticised Sir John’s intervention, in which he held out the possibility of another referendum on the final deal, one describing it as “un-statesmanlike” and full of “cheap comments”.
But the message will be reiterated by former Labour prime minister Tony Blair later in a speech in Brussels.
He will call for the public to have a “real choice” while urging the EU to put forward new ideas to address “genuine underlying grievances beneath the Brexit vote, especially around immigration”.
In a new report, the Commons Business Committee warned failure to reach any kind of deal would be potentially calamitous for the car industry and only close alignment with the EU would ensure its survival.
But on Tuesday the industry received a vote of confidence when Toyota said it would build the next generation of its Auris hatchback at its Burnaston plant in Derbyshire, safeguarding more than 3,000 jobs.
US President Donald Trump has told a group of lawmakers not to be so “petrified” of the powerful gun lobby the National Rifle Association (NRA).
During a bipartisan meeting to discuss gun reform, Mr Trump encouraged lawmakers to come up with comprehensive legislation on the matter.
Mr Trump suggested expanding background checks for gun buyers and raising the legal age to buy rifles to 21 from 18.
He held the meeting in the wake of a school shooting that left 17 dead.
“They have great power over you people,” the president said of the NRA to his fellow Republicans on Wednesday.
“Some of you are petrified of the NRA,” he continued. “You can’t be petrified.”
Mr Trump, who was endorsed by the NRA in his 2016 presidential campaign, has treaded carefully when speaking about gun reform after the 14 February school shooting in Parkland, Florida.
He met NRA leaders over the weekend after speaking to students from Marjory Stoneman Douglas High School, where the tragedy took place, as well as other families affected by school shootings in a listening session last week. He also discussed school safety with governors earlier this week.
Wednesday’s meeting came as students at the Florida school where 17 people were killed returned to classes.
During the meeting, Mr Trump reiterated some of his earlier proposals to strengthen background checks and restrict access to weapons for the mentally ill, but also said he would consider raising the age to buy rifles from 18 to 21, an idea opposed by the NRA.
Seventeen Democrats and Republicans, some who want more gun restrictions and others who are against tightening laws, were invited by the president to the hour-long meeting about potential ways to address school safety.
“It would be so beautiful to have one bill that everybody can support, as opposed to – you know – 15 bills, everybody’s got their own bill,” Mr Trump said on Wednesday.
During an exchange with Senators Pat Toomey and Joe Manchin, who have worked on a bill to strengthen background checks for gun purchase, Mr Trump asked whether they included a provision to raise the legal age to buy a gun to 21. Mr Toomey said they did not.
“You know why? Because you’re afraid of the NRA,” Mr Trump said.
He also suggested the alleged Florida gunman, who police say raised several red flags before the tragedy struck, should have had his guns taken away, regardless of the law.
“I think they should have taken them away, whether they had the right or not,” the president said.
He later added: “Take the guns first, go through due process second.”
Mr Trump also warned lawmakers against proposing a bill that included concealed carry reciprocity among states, a provision Republicans and the NRA have aimed to include in any gun legislation.
Democratic Senator Chris Murphy of Connecticut, where the 2012 Sandy Hook massacre occurred, told the president that previous efforts to pass bills requiring strong background checks have been met with opposition because of the NRA, and warned him against underestimating the group’s power on Capitol Hill.
“The reason that nothing’s gotten done here is because the gun lobby has had a veto power over any legislation that comes before Congress,” Mr Murphy said.
Mr Trump deflected the warning and said he had previously told NRA officials: “It’s time. We’ve got to stop this nonsense. It’s time.”