The labour party was voted in to form the UK Government in 1964 and one of its policies was to reduce the countries defence spending. By April 1967 it decided that it would half it's commitment to the Far East Command by 1971 and remove all military personnel by 1975. However, in November 1967, increasing problems with Britain's economy forced it to devalue the pound which, in turn, led to deep cuts in the its budget. It became clear that Britain could no longer maintain its military commitments in the Far East and later announced its withdrawal of all troops in South East Asia by 1971 – four years earlier than planed.
This was devastating news for the Government & people of Singapore as the military bases contributed to over 20% of its Gross Nation Product and provided 10% of the employment in the country. It would also leave a large gap in its defences as their own military forces were in it's infancy.
Singapore's The Prime Minister, Lee Kuan Yew, and Minister of Finance, Goh Keng Swee, when to London. Where they met with British political leaders an ralied support through television appearances etc. Dispute this, on 16th January 1968 the British government announced that they would Pull out from South East Asia by 1971. However, as a compromise, the British agreed to extend the deadline from March to December 1971.
Hence the RAF Station at Seletar was handed over to the Singapore Armed Forced (Tentura Singapura) in March 1971.