Prime Minister Keir Starmer announced on Tuesday that Britain would recognize the state of Palestine in September if Israel does not agree to a cease-fire with Hamas, pouring pressure on the Israeli government to halt a war that has put Gaza on the brink of famine.
Mr. Starmer’s announcement, which came after an emergency meeting of his cabinet, is a sharp shift in his position, reflecting the intense political pressure his government has faced as the British public and lawmakers in his own Labour Party recoil from images of starving children in Gaza.
Mr. Starmer cast recognition as part of a broader European effort to end the ruinous war between Israel and Hamas. He reiterated that Hamas must release its remaining hostages, sign up to a cease-fire and accept that it will have no role in the future governing of Gaza.
But Mr. Starmer’s statement was aimed squarely at Israel, dramatizing how swiftly sentiment has changed among Western countries about how to end the war. Britain followed in the steps of France, which announced last week that it would recognize an independent Palestinian state at the United Nations General Assembly in September.
“The situation is simply intolerable,” Mr. Starmer said after the cabinet meeting. “I am particularly concerned that the very idea of a two-state solution is reducing and feels further away today than it has for many years.”
In addition to a cease-fire, Mr. Starmer said the Israeli government would have to agree not to annex the occupied West Bank and to commit to a peace process that would result in a Palestinian state alongside Israel.
These are demands that Israel is highly unlikely to accept under Prime Minister Benjamin Netanyahu’s right-wing government. Mr. Netanyahu recently said that a Palestinian state could be “a launchpad to annihilate Israel.”
Britain’s decision will deepen Israel’s diplomatic isolation after it abandoned a truce with Hamas in March and resumed its military offensive in Gaza. It also carries significant symbolic weight, given Britain’s diplomatic stature and history in the Middle East.
Britain played a critical role in the creation of the state of Israel by declaring in 1917 that it supported the establishment of a “national home for the Jewish people” in what was then Palestine.
Mr. Starmer had been ambivalent about recognizing a Palestinian state, several officials said, in part because he viewed it as a “performative” gesture that would not change the situation on the ground and could, in fact, complicate efforts to negotiate a cease-fire between Israel and Hamas.
But a chorus of warnings about rising starvation in Gaza, after Israeli restrictions on the delivery of food, changed his calculation. More than 250 lawmakers, including many from Labour, signed a letter to Mr. Starmer and the foreign secretary, David Lammy, urging Britain to recognize a Palestinian state at a U.N. conference this week that is devoted to the two-state solution.
Speaking at the conference on Tuesday, Mr. Lammy evoked Britain’s role in the creation of Israel, noting that the Balfour Declaration, the diplomatic statement issued by the British government in 1917, vowed that “nothing shall be done, nothing that will prejudice the civil and religious rights” of the Palestinian people.
“This has not been upheld,” he said, “and it is a historical injustice that continues to unfold.”
Mr. Lammy said that Britain was carrying out airdrops of humanitarian aid along with Jordan, evacuating injured children to British hospitals and working for the resumption of the U.N.’s relief assistance.
For Mr. Starmer, a methodical former human rights lawyer, the agonizing scenes in Gaza clearly moved him and changed his calculus.
“We will keep working with all our international partners to end the suffering, get aid flooding into Gaza and deliver a more stable future for the Middle East,” he said. “Because I know that is what the British people desperately want to see.”