 This division suffered such heavy casualties during the early stages of the campaign, that the 1st Leicesters and the 2nd East Surreys were forced to amalgamate, becoming the British Battalion and the 1/8th Punjab and the 2/9th Jats were also amalgamated, becoming the Jat-Punjab Battalion.The 6th and 15th Infantry Brigades were also amalgamated becoming the 6th/15th Indian Infantry Brigade.After the Battle of Jitra the 11th Division, under Major-General Paris, inflicted heavy casualties on the Japanese at the Battle of Kampar, but was almost completely destroyed at the Battle of Slim River.