 Now, it was the newly-imprisoned Japanese troops under British captivity which were then made to improve both runways, reinforcing the north-south runway for military aircraft and adding perforated steel plates on the east-west runway.Completed post-war, non-flying RAF Chia Keng — a GCHQ radio-receiving station, was a satellite station of RAF Changi (being the Headquarters Air component part of British Far East Command) until the withdrawal of British troops from Singapore at the end of the 1960s.Also, the nearby RAF Hospital Changi (now defunct as Changi Hospital and more prominently known as Old Changi Hospital, OCH) functioned as the primary British military hospital which provided medical care for all British, Australian and New Zealand servicemen (collectively, these three Commonwealth states which based troops in Singapore became known by the term "ANZUK", for Australia, New Zealand and the UK) stationed in the eastern and northern parts of Singapore while Alexandra Hospital was directed for those stationed in the southern and western areas of Singapore.