 Complete the following phrase:  During the opening period of the Second World War, 20 Squadron continued its air control work on the Northwest Frontier.  After Italys entry to the war, defence of Indias ports was assigned a higher priority; on 14 February 1941 A and B Flights moved to Bombay and Madras respectively to provide reconnaissance and attack for coastal defence.  These flights re-joined the rest of the Squadron at its new headquarters at RAF Secunderabad on 10 June 1941. It was re-equipped with Westland Lysanders in December 1941, remaining in the army co-operation role.  After Japans entry to the war on 7 December 1941, Japan 