The government approved construction of the Tsuen Wan Line in 1977, then known as Tsuen Wan Extension, and works commenced in November 1978. The project added a 10.5-kilometre section to the MTR system, from Prince Edward to Tsuen Wan. The line started service on 10 May 1982 with a total cost of construction (not adjusted for inflation) at HK$4.1 billion.