In 1901 all companies to the east of the River Wandle were included in the South London Battalion. This included large areas of what is now Lambeth, Southwark & Lewisham. Companies to the West  of the River Wandle were unattached to a Battalion until 1903 when the Thames Valley Battalion were planned.

In 1926 the Boys’ Brigade merged with the Boys’ Life Brigade. A number of Boys’ Life Brigade Companies were merged into the South London & Thames Valley Battalions.

In 1941 The South West London Battalion was formed and included all companies in the Metropolitan Boroughs of Wandsworth & Battersea.

In 1965 the South West London Battalion boundary was changed to match those of the London Borough of Wandsworth and the Battalion name was changed to the Wandsworth Battalion.

In 1984 the Wandsworth Battalion was extended North of the Thames to include the South West Post codes in Fulham & Chelsea.

In 1993 the Battalion changed its name back to South West London to reflect the wider geographic area.