On 20 January, further Japanese landings took place at Endau, in spite of an air attack by Vildebeest bombers. The final Commonwealth defensive line in Johore of Batu Pahat–Kluang–Mersing was now being attacked along its full length. In the face of repeated requests from his Chief Engineer, Brigadier Ivan Simson, Percival had resisted the construction of fixed defences in Johore, as on the North shore of Singapore, dismissing them with the comment, "Defences are bad for morale." On 27 January, Percival received permission from the commander of the American-British-Dutch-Australian Command, General Archibald Wavell, to order a retreat across the Johore Strait to the island of Singapore.