The British Army had one formidable offensive force, Japanese Army, that took a toll on her military. To counter this, they formed a commonwealth army which consisted of the Burma, India, East and West Africa, and units of the British Army.
Primarily, the Multi-national Force was the British Fourteenth Army whose significant role was to counter the operations of the Japanese. The force was formed in 1943 in Eastern India under Lt. General William Slim to handle rear operations.
The fourteenth army was divided into two: the Eastern Command and the fourteenth British Army. The western Command would report to GHQ India and handle rear operations in Bihar, Odisha, and Bengal, while the 14th British Army would be responsible for countering the Japanese.
The Japanese began to destroy the allies base areas in 1944. They attacked the 14th army as they were advancing south at Arakan and they, Japanese, overran the Indian division. However, the surrounding units defeated the Japanese force in the Battle of the Administration restoring supplies by aircraft.
The fourteenth army continued to play significant courses in World War II like the Battle Of Central Burma where they seized the logistic communications of the Japanese at Mektila and recaptured Mandalay which was the capital at the time.
The Fourteenth army captured Rangoon too which was a strategic port that allowed the military to get supplies during the monsoon. After the defeat of the Japanese, the Fourteenth Army was redeployed to Ceylon to assist in the recapturing of the Himalaya and Singapore. This time under General Miles Dempsey after the promotion of William slim.