On April 13, 2026, the day U.S. Central Command's blockade of shipping to and from Iranian ports was set to begin at 10 a.m. ET, after weekend U.S.-Iran talks failed, Britain said it would not take part. “We're not supporting the blockade,” Prime Minister Keir Starmer told BBC Radio 5 Live. “My decision has been very clearly that whatever the pressure, and there's been some considerable pressure, we're not getting dragged into the war,” he said, adding that Britain would not join without a “clear lawful basis” and a “clear thought-through plan.”
CENTCOM said the blockade would be “enforced impartially against vessels of all nations entering or departing Iranian ports and coastal areas” but would not impede ships transiting the strait to and from non-Iranian ports. Trump had insisted that “many other countries” would help, The New Republic reported. Instead, French President Emmanuel Macron said France and the UK would work with dozens of countries on the disruption “separate from the warring parties,” and Starmer said the two would co-host a summit, which TNR reported would include more than 40 nations, “to advance work on a coordinated, independent, multinational plan to safeguard international shipping when the conflict ends.” Spanish Defense Minister Margarita Robles said the blockade plan “makes no sense.”
As of TNR's publication, the 10 a.m. deadline had passed with no confirmation that the blockade was in place, and Iran's Revolutionary Guard had warned that any warships approaching the strait would be considered a ceasefire violation. Brent crude rose to about $102 a barrel on the morning of April 13, up from about $65 before the war began in late February. TNR reported gasoline above $4 a gallon in the U.S. (up to $7 in parts of California), about $7.50 in the UK, over $8 in France and over $10 in the Netherlands.
Correction (October 2, 2026): This entry quoted Starmer as saying “We are not supporting the blockade. The UK is not getting dragged in”; the second sentence was The New Republic's paraphrase, and Reuters quotes him as saying “We're not supporting the blockade” and “we're not getting dragged into the war.” The entry also described the blockade as covering the whole strait; CENTCOM said it targeted vessels entering or leaving Iranian ports. The claim that no country joined was narrowed to what the sources report: Britain declined, France planned a separate effort and Spain criticized the plan. The original New Republic link served a different article and was replaced with the correct one.