In October 1939, Commander-in-Chief, Home Forces, General Walter Kirke, was tasked with drawing up a defensive plan to defend the United Kingdom from a German invasion, which was codenamed Julius Caesar. The divisions assigned to this defensive plan were constantly changing, and, by May 1940, included the 66th Division. The division replaced the 49th (West Riding) Infantry Division in Northern Command's part of this plan, and as a result moved from positions around Manchester into Yorkshire. The division's role was to launch an immediate attack on German parachutists, or failing that, to cordon off and immobilise any German invasion effort, until relieved by forces capable of launching a counter-attack to defeat the Germans. On 9 April, following the German invasion of Norway, the second-line infantry divisions in the United Kingdom were requested to each form an independent infantry company consisting of 289 volunteers, who would be deployed to Norway. The 66th Division formed No. 10 Independent Company. However, the company was not deployed to Norway. Following the conclusion of the campaign, No. 10 Independent Company was based in Scotland and did not return to the division. In May 1940, the divisional artillery was equipped with only seven First World War howitzers against a war establishment of seventy-two modern 25-pounder field guns. Historian David John Newbold described all forces under Kirke's command in May, including the 66th, as having "been severely weakened by departures overseas", "spread very thinly" and "largely semi-trained, relatively immobile and lacking in all types of heavy equipment, especially artillery and anti-tank guns." In particular, the division relied heavily on civilian transport. It had, prior to moving to Yorkshire, conducted little training. The move, it was hoped, would rectify this situation. Shortly after transferring, the division began platoon and company size training exercises.