From Japan Runs Wild, 1942–1943, by Peter Harmsen (War in the Far East, Book 2; Casemate, 2020), Kindle pp. 69-70:
The retreat out of Burma into India was a race against time, as it had to be completed before the onset of the monsoon. The troops made it, just. The last stage of the British withdrawal was bogged down by torrential rains, which began in May. Pearl “Prue” Brewis, a British nurse, was on a train that managed to travel 65 miles in six days, since movement could only take place at night. On the sixth day, while the carriage was sitting idly on the tracks, a senior railway official entered and offered a ride up north on his train. It was crowded, but fast. “Standing room only, you know,” Brewis said about the 100-mile ride north. “Actually, we got the last plane to leave Burma because the next day the aerodrome was bombed.”
More than a million Indians lived in Burma prior to the war, but most still considered India their home. When the Japanese launched their invasion, there was a mass exodus of Indians, and soon most major Burmese cities were virtually emptied of them. The senior medical officer, Brigadier Short, described the Indians who arrived at the town of Ledo in easternmost India in the summer of 1942: “Complete exhaustion, physical and mental, with a disease superimposed, is the usual picture… all social sense is lost… they suffer from bad nightmares and their delirium is a babble of rivers and crossings, of mud and corpses… Emaciation and loss of weight are universal.” Slim watched how an Indian woman died from smallpox, leaving behind her small son. He and his staff bribed an Indian family to take the boy with them. “I hope he got through all right and did not give smallpox to his new family,” Slim wrote in his memoirs.
In the manner of Dunkirk, the defeat in Burma was in a way turned into a victory by the British. “The Army in Burma,” the official British history says, “without once losing its cohesion had retreated nearly one thousand miles in some three and a half months—the longest retreat ever carried out by a British Army.” The American assessment of the British record was less kind: “Though there were cases of individual heroism and desperate fights by small isolated forces, the main body of the British made little or no efforts to stand and give battle,” an official US military report on the Burma campaign said. “The piecemeal defense was a piece of stupidity which resulted in tens of thousands of casualties to the troops, the complete destruction of every town and city in Burma, and the loss to both the Chinese and the British of a vast amount of irreplaceable installations and equipment.”