Trump's threat is the latest demonstration of how the "special" relationship between the U.K. and U.S. has become fractured since the start of the Iran war.

At stake may be the future of the "special relationship" between the two countries, forged during World War II and now imperiled.

As Britain rejects U.S. blockade tactics against Iran, King Charles III's visit to Washington is shaping up as a critical diplomatic balancing act.

His state visit begins after a gunman rattled Washington, but U.K. officials hope pomp can paper over an Iran war fracture and remind the president of the alliance's perks.

President Donald Trump hosts King Charles III at the White House as tensions rise over Iran and NATO during a rare state visit.

King Charles's trip to the US comes at a time of strained relations between Washington and London over the Iran war.

The King and Queen have been officially welcomed to the US by Donald Trump with an unprecedented military ceremony on the lawn of the White House.Charles and Camilla watched the display with President Trump and first lady Melania alongside a group of dignitaries and hundreds of spectators.