The division was again serving under Western Command. In April 1942 the division was sent to defend Kent in South-Eastern Command, under Lieutenant-General Bernard Montgomery, between 1942–1943, joining XII Corps ready to defeat a German invasion (Operation Sea Lion), serving with the 43rd (Wessex) Infantry Division and 46th Infantry Division. The 53rd Division was later earmarked to form part of the Second Army for the invasion of Europe.