The first section of the line was opened between Walthamstow Central and Highbury & Islington on Sunday 1 September 1968. There was no official opening ceremony. The first train left Walthamstow Central for Highbury & Islington at 6.30 am. The opening of the line also saw the first introduction of automatic ticket collection barriers and a new bus terminal at Walthamstow Central being constructed. Later that year, the section between Highbury & Islington and Warren Street was opened, again without any ceremony. The official opening ceremony of the line took place at Victoria station on 7 March 1969 when Queen Elizabeth II unveiled a commemorative plaque on the station concourse. After a short ceremony, Her Majesty bought a 5d ticket (five old pence = 2.08p) and travelled to Green Park. Princess Alexandra later opened the Brixton extension on 23 July 1971, with her also making the journey from Brixton to Vauxhall. Trains on the line then ran every two minutes during peak periods.
