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 and Lewisham. Companies to the West of the River Wandle were unattached to a Battalion until 1903, when the Thames Valley Battalion was 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 and Thames Valley Battalions.

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

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

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