barracks designed for 1,000. During his first month at the camp, Blackburn began a diary using an old ledger, which he maintained for much of his internment against the explicit orders of the Japanese. At one point he removed the covers from the ledger and hid the pages inside the lining of his raincoat. The food rations at the Bicycle Camp were poor, and because Japan was not a party to the Geneva Convention Relative to the Treatment of Prisoners of War and did not follow its stipulations, it was difficult to maintain discipline as all but Blackburn had to work regardless of rank. Blackburn arranged activities to alleviate the boredom and consistently stood up to the Japanese. He was interrogated and was struck by a guard on at least one occasion, but was spared any torture. More junior officers were subjected to torture, beatings and other abuse. The Japanese tried to persuade Blackburn and others to participate in propaganda radio broadcasts, but Blackburn gave orders against it and refused to do so himself. In June, the Japanese ordered all prisoners to sign a form stating that they would comply with all orders and would not resist their captors. Blackburn only signed after appending "except where contrary to my oath of allegiance to His Majesty the King". When another form was produced, requiring an oath to be sworn, Blackburn refused. Privileges were withdrawn, dozens of officers and men were beaten, and Blackburn was placed in solitary confinement. In the end, when the Americans decided to sign, Blackburn agreed in the interests of unity and ordered all the troops to sign. By the end of July, Blackburn was conscious that he had lost about in weight due to the poor rations. Blackburn was promoted to substantive colonel on 1 September 1942, but retained his temporary rank of brigadier whilst in captivity. In the same month, he began to suffer from depression and fell ill with dengue fever. The Japanese commandant was replaced with a stricter man, and the guards were replaced with Koreans, who quickly earned a reputation for cruelty. Beatings were conducted for minor infractions, such as failing to stand to attention quickly enough. In early October, 1,500 POWs left the camp, including almost all of the 2/2nd Pioneers, destined for the Thailand–Burma railway. Another group of 84 left a few days later, but the losses were soon made up