New Delhi, May 15 -- Efforts to unseat British Prime Minister Keir Starmer from within his own party broke into open rebellion Thursday, with one potential rival resigning from the Cabinet and two others positioning themselves for a future leadership challenge.

Health Secretary Wes Streeting became the first senior minister to quit Thursday in what was seen as a precursor to challenging Starmer's leadership. He said he had lost confidence in Starmer, who should not serve out the rest of his term.

"You have shown courage and statesmanship on the world stage - not least in keeping Britain out of the war in Iran," Streeting wrote in an excoriating resignation letter. "But where we need vision, we have a vacuum. Where we need direction, we ...