The Territorial Force was a part-time volunteer component of the British Army. A County Territorial Association was a body created to administer units of the Territorial Force located within an area largely defined by existing county boundaries of the UK. There was one for the County of London and another for the City of London. Each association was led by a Lord Lieutenant acting as president, along with a chairman and a vice-chairmen.
Stepping Forward London has a lot of information about the London units.
The current day Army Reserve was known as the Territorial Force 1908-21, the Territorial Army 1921-67, the Territorial and Army Volunteer Reserve 1967-79, and again the Territorial Army 1979 - 2014.
