Canada and Australia joined the UK in recognizing a Palestinian state at the United Nations General Assembly meeting in New York.
Britain said on Sunday it was recognising a Palestinian state after Israel failed to meet conditions including a ceasefire in the nearly two-year-old Gaza war.
"Today, to revive the hope of peace for the Palestinians and Israelis, and a two-state solution, the United Kingdom formally recognises the State of Palestine," Prime Minister Keir Starmer said on X.
London's step aligns it with more than 140 other nations but will irk both Israel and its main ally the United States.
The decision carries symbolic weight as Britain played a major role in Israel's creation as a modern nation in the aftermath of World War Two and has long been its ally.
Canada and Austr