With Japan's entry into the war, and especially after the fall of Singapore, Ceylon became a front-line British base against the Japanese. Admiral Sir Geoffrey Layton was appointed Commander-in-Chief, Ceylon. Air Vice Marshal John D'Albiac became Air Officer Commanding. Admiral Sir James Somerville was appointed commander of the British Eastern Fleet. Somerville retreated with his main fleet to Addu Atoll in the Maldives, leaving the aircraft carrier Hermes, escorted by the heavy cruisers Cornwall and Dorsetshire, and the Royal Australian Navy destroyer HMAS Vampire in Ceylon.
After the sinking of Prince of Wales and Repulse and the fall of Singapore, British morale on the island dropped. The sinking of these two capital ships shocked much of the world; the awareness of the superiority of aircraft carriers over battleships increased dramatically. On Ceylon there was understandably much anxiety that a Japanese attack appeared to be inevitable. A large sea turtle which came ashore was reported by an Australian unit as a number of Japanese amphibious vehicles. However, actual preparations for defence were lackadaisical, apart from the deployment of a Royal Air Force squadron at the Colombo race course. Anti-British sentiment increased accordingly within some portions of the indigenous population and their hopes ran high for liberation by the Japanese.
On 4 April 1942 the Japanese Navy fleet of Admiral Chuichi Nagumo was located by a Catalina aircraft flown by Squadron Leader Leonard Birchall out of Koggala. However, Nagumo achieved near-complete surprise when he launched an airstrike on Colombo the next day (Easter Sunday, 5 April). Despite the fact that the war in Europe had been raging for almost 18 months, and in the Pacific for almost four, the British radars were not operating because it was Sunday.
But the greatest shock of the day was probably felt by the Japanese high command, who had expected to catch the remnants of the British fleet at anchor in ...