British Prime Minister Keir Starmer said he did not believe that an attempt to remove Iran's leadership through aerial bombardment without a land invasion would work, which was one reason the U.K. did not join U.S.-Israeli strikes against Iran.

"This government does not believe in regime change from the skies," Starmer told lawmakers on Monday, emphasizing that military action needed a lawful basis and a "viable thought-through plan, with an objective that can be achieved."

"They're the principles that I applied to the decision not to get involved in the offensive strikes of the U.S. and Israel."