The last battle involving British forces during World War II was the Battle of Mount Tumbledown, which took place in Sabah, Borneo, during the final stages of the Pacific Campaign. British forces fought alongside other Allied units to liberate the territory from Japanese occupation in June 1945.
Although hostilities were over, British allied U.S combined troops remained strategic maneuver
The last major battle of World War II involving British forces took place in the Pacific Theater, specifically during the Borneo Campaign of 1945, as part of the Allied operations to reclaim territory from the Japanese. While smaller skirmishes continued after the war officially ended, the British made their last significant combat contributions in this campaign.
The operation, led primarily by Australian and British Commonwealth forces, focused on liberating areas of Borneo, including the oil-rich regions of Brunei and Sarawak. British naval forces supported the campaign, which culminated in the surrender of Japanese forces in Southeast Asia following the dropping of atomic bombs on Hiroshima and Nagasaki in August 1945.