From the Wikipedia page [1]
Sir William Lane-Mitchell (24 January 1861–1940) was a British Conservative Party politician. He was elected as the Member of Parliament (MP) for Streatham in 1918, and held the seat until his resignation in 1939 by becoming Steward of the Manor of Northstead. He was knighted in 1921.
Twice Mayor of Camberwell - 1906-07, and then, following the death of the next Mayor, John Adam Markillie on 22 August 1908, elected to complete the term of office 2 September 1908).
Some detail here [2].