The Devonport and District Tramways was sold to the Corporation in 1914 (although the tracks of the two networks were not connected until October 1915) but the Plymouth, Stonehouse and Devonport Tramways, which dated back to 1872, remained an independent company until 1922 when it too was sold to the Corporation.
In 1914, the Devonport and District Tramways were purchased by the Corporation (even though the tracks of both networks weren't connected until October 1915), whereas the Plymouth, Stonehouse, and Devonport Tramways, founded in 1872, remained an independent company until 1922 when it was also bought by the Corporation.