He was then appointed as the Second in Command of the 1/15th Punjab Regiment in the 14th Indian Infantry Division and saw action in the first, Arakan campaign of 1942-43 against the Japanese, 55th Division. After being withdrawn due to illness he rejoined the battalion in time for its advance with the 19th Indian Infantry Division across the Chindwin into the Shwebo plain and the advance on Mandalay. He was then appointed to command the 3rd Btn 6th Rajputana Rifles,of the 19th Indian Infantry Division, in early 1945, he was in command during the final stages of the Burma campaign and the capture of Rangoon. He was awarded the DSO in the Karen Hills east of Toungoo in central Burma, while commanding his battalion in the fight to halt a Japanese counter-attack astride the Mawchi road which was attempting to the Fourteenth Army’s line of communication. He was also mentioned in dispatches for his part in mopping-up operations after the Japanese surrender in August 1945. After the independence and Partition of India in 1947, Prendergast transferred from the Indian Army and received a British Army commission into the York and Lancaster Regiment in 1948. He was next appointed as the British defence attaché in Kabul due to his knowledge of the region, with the local rank of colonel. In 1950 he reverted to the rank of major to join the 1st Battalion, York and Lancasters in Brunswick, Germany and in 1951 was appointed to command the battalion, which at the time was part of a lorried infantry brigade in an armoured division. In 1952, he was promoted colonel again for a staff appointment at HQ 1st British Corps in Germany. His final appointment in the army was commander of the 147th Brigade of the Territorial Army (TA) based in Leicester. On his retirement he travelled widely and published the books, "The Road to India", a guide to motoring in the sub-continent, "A Plume of Dust", about travel in Central Europe, and a light-hearted autobiography, "Prender’s Progress".