In 1896, the U.K. was on one side of the shortest war in history. Who did it fight?
The Anglo-Zanzibar War lasted between 38 and 45 minutes, depending on whom you ask. It ended with a British victory. Sultan Khalid bin Barghash seized power in Zanzibar without authorization of British colonial rule, which resulted in a tense stand-off and eventual bombardment by the British Navy. That conflict was the duration of the war. Source: Historic UK