Sir Keir Starmer is facing a Labour revolt over Brexit after he vowed not to take Britain back into the Single Market.
In a keynote speech on Britain’s future outside the European Union, Sir Keir pledged to “make Brexit work” and said he would not seek to join the Single Market or a customs union.
But before he had even delivered his remarks, the Labour leader faced a backlash from within his own ranks, with Sadiq Khan, the Mayor of London, openly contradicting him.
It comes as Sir Keir is expected to find out this week whether he will be fined over beergate, when he was caught on camera drinking a beer in a local MP’s office after a day of campaigning for local elections last spring.
At the time, Covid rules meant indoor gatherings were banned except for work purposes.
Sir Keir has always maintained that he did not break any rules on the basis that the dinner was work-related, but has promised to resign if he is sanctioned and reiterated that promise on Monday.
Mr Khan is seen as a potential contender should the Labour leader be forced to stand down.
Speaking on Monday, Sir Keir said: “Under Labour, Britain will not go back into the EU. We will not be joining the Single Market. We will not be joining a customs union.
“We will not return to freedom of movement to create short-term fixes. Instead, we will invest in our people and our places and deliver on the promise our country has.”
However, speaking to the BBC ahead of the speech, Mr Khan said he believed the UK should join the EU Single Market because it would make the country’s future “more prosperous”.
Told that it sounded as though he disagreed with Sir Keir, he replied: “Keir’s job is to be leader of the Labour Party, my job is to be the Mayor of London. That’ll mean on many occasions I agree with the Labour Party, on some occasions I may disagree.
“Londoners elected me to be their champion, their advocate. I believe that our city and our country’s future is best served being members of the Single Market.”
Mr Khan was not the only senior Labour figure to voice dissent against the party line. Stella Creasy, the MP who chairs the Labour Movement for Europe, said: “We are only just beginning to understand the damage Brexit is doing to Britain.
“So we urge Keir to make sure nothing is off the table as a solution in the fight to tackle the cost of living crisis and protect jobs, trade and security.”
Sir Keir’s position on Brexit also potentially puts Labour on a collision course with the Liberal Democrats, whose stated aim is to rejoin the Single Market.
Labour and the Liberal Democrats have been accused of operating an unofficial pact in order to win by-elections amid speculation they could form a coalition in the event that Labour wins a general election, but without enough seats to form a majority.
In that situation, the Lib Dems could put pressure on Labour to back down on their Brexit stance.
In the behind-closed-doors speech for the Centre for European Reform think tank, Sir Keir acknowledged that his Brexit position would not please everyone in his party.
After stating that Labour would not rejoin a customs union or the Single Market, he said: “I know some people don’t want to hear that, but it is my job to be frank and honest – you will always get that with me.
“Nothing about revisiting those rows will help stimulate growth or bring down food prices or help British business thrive in the modern world.
“It would simply be a recipe for more division, it would distract us from taking on the challenges facing people and it would ensure Britain remained stuck for another decade.”
Sir Keir also used the speech to set out how he would fix the Northern Ireland Protocol by eliminating most border checks and creating a new veterinary agreement for agricultural products between the UK and EU.
“We will work with business to put in place a better scheme to allow low-risk goods to enter Northern Ireland without unnecessary checks,” he said.
He added he would tear down unnecessary barriers to trade as well as strengthening security cooperation with European allies.
Sir Keir campaigned to remain in the EU during the 2016 referendum, before serving as Jeremy Corbyn’s shadow Brexit secretary and backing a second referendum.
But his speech on Monday was his strongest signal yet that he now wants to steer the party away from any association with the Remain camp.
Last month, a shadow minister said Labour would seek to at least rejoin the EU’s Single Market and a customs union once in power.
Anna McMorrin, a shadow justice minister, told supporters that Labour should renegotiate the current deal with the EU, suggesting that could be a path to rejoining fully.
Speaking to the Labour in Communication group, Ms McMorrin said when asked whetherBritain could return to the Single Market: “I hope so, I really hope so.”
But she later rowed back on her comments, saying: “Labour policy on Brexit is clear. We have left the EU, Labour voted for the deal. It is now the job of all of us to make it work.”
David Lammy, the shadow foreign secretary and another potential leadership candidate, has also backed reworking ties with Brussels.
“Of course, if we were in government there are aspects of our relationship with the European Union that do need to be determined,” he told LBC last month.