After the war he continued to command the 51st Division in Germany until March 1946 when he selected to command the 6th Airborne Division. The division, which had fought with distinction in Northwest Europe, was then serving in Palestine during the Palestine Emergency (for further information see 6th Airborne Division in Palestine). Cassels's time there was not altogether happy. "I was in Palestine from March 1946 until the end of the year, ten hellish months. I got appallingly rude letters from America, saying that I was much worse than Hitler, addressed to me personally. We nearly had seizures every time we read a newspaper. The general line was that we were anti-semitic beasts and murderers. I don't think they realized that many of my men had parachuted into Normandy in June 1944. Large numbers of them were killed and wounded fighting to remove Hitler from the face of the earth." "It did make one hopping mad to see some of the comments in the Press...denigrating all or most of our actions. They sat in comfort and safety in England while we lived in fairly uncomfortable conditions and under the continued...threat of being blown up!!" For his services in Palestine he was mentioned in despatches.