Why did Britain keep military bases at Akrotiri and Dhekelia after Cyprus became independent?

Under the 1959 London Agreement, the United Kingdom retained sovereignty over the military bases at Akrotiri and Dhekelia to serve as strategic military assets.123

These sovereign base areas, which total 99 square miles (256 square km), were established to function as British training facilities and vital staging areas for operations between Britain, southern Asia, and the Far East. Additionally, the bases provide essential support for United Nations forces stationed on the island. The retention of these areas was a formal condition of the treaties that granted Cyprus its independence in 1960.1324