President Trump has fumed repeatedly about Britain’s failing to help the U.S. wage war on Iran. The United Kingdom responded by allowing U.S. bombers to strike Iran from southern England, while Britain’s fighter jets have flown thousands of defensive missions across the region.

Now the British military is embarking on yet another phase: to secure the Strait of Hormuz if the war comes to an end, dispatching an advanced destroyer to the region and another ship armed with autonomous mine-hunting equipment. The move to remove mines from the waterway could also serve to deflect further criticism from Mr. Trump.

The war with Iran was not Britain’s making, but the country cannot escape the conflict’s far-reaching effects. Halted traffic in the strait has crippled international shipping and driven up energy prices in the United States and around the world.

The British military took a handful of reporters on Friday to Gibraltar, a small patch of British territory at the tip of Spain. The trip seemed like an effort to highlight its military capabilities and resolve, and to show the Trump administration that a close ally was doing its part.

The special relationship the two countries enjoy has frayed on the surface since Mr. Trump entered the White House.

At Gibraltar, Al Carns, Britain’s armed forces minister and ex-Royal Marine officer with extensive combat experience, brushed off U.S. criticisms. He said that the U.K. had had “more jets in the Middle East than we’ve had for 15 years” and that “we’ve shot down over a hundred drones.”