Starmer has defied calls to quit from about 90 Labour MPs who blame him for heavy losses in local elections on May 7 and say he has failed to deliver reforms since coming to power in a landslide 2024 election victory.
While almost a quarter of the prime minister's elected MPs have called for him to go and a handful of junior ministers have resigned in protest, potential rivals for his job have yet to trigger a formal leadership challenge.
Wes Streeting, Britain's health minister who is seen as a leadership rival who could move against the prime minister now, spent less than 20 minutes in Downing Street early on Wednesday for a meeting with Starmer, which had been dubbed by British media as a showdown.
But an ally of Starmer, Europe minister Nick Thomas-Symonds, said no candidate appeared to have the backing of enough MPs to trigger a challenge, and that it did not look likely either.
"We now have to move on," he told BBC Radio.
Starmer will on Wednesday take part in the State Opening of Parliament - a grand ceremony led by King Charles which is used by the government to set out its political priorities and legislative agenda for the year ahead.
"Britain stands at a pivotal moment," Starmer said in a statement.
"To press ahead with a plan to build a stronger, fairer country or turn back to the chaos and instability of the past."
He said Britons expected the government to focus on cutting the cost of living, bringing down hospital waiting lists and keeping the country safe in an "increasingly dangerous world".
A package of more than 35 bills and draft bills will focus on measures to improve the economy, strengthen national security and "reform the state to support a more active government that is on the side of British people".
After travelling to parliament and donning the Robe of State, the King will read a speech written by Starmer's government setting out the planned new laws.
But the implementation of that speech remains as uncertain as Starmer's political future; if he were to be ousted, his successor would not be bound to follow the same plan.
After spending much of Tuesday behind closed doors at his Downing Street office as he sought to rally support, Wednesday's ceremony will put his struggle for power back in public view.
Under the gaze of television cameras and alongside leaders of rival parties, Starmer will walk in a procession with MPs from parliament's lower house to its upper house, where the King will then speak.
Starmer will later deliver a speech in a parliamentary debate that is likely to be used by rivals to ridicule his position as a leader with badly damaged authority presenting an agenda that he may never get to deliver.
Just a few hours before the event, a group of unions close to the Labour Party said Starmer must go.
