The 9th (County of London) Battalion, The London Regiment (Queen Victoria's Rifles), was formed on 1 April 1908 by the amalgamation of regiments under the Territorial and Reserve Forces Act 1907. Their Wikipedia page gives details about the origins of the battalion and how it has been absorbed into other regiments over subsequent years.
The London Regiment ceased to exist in 1938 and their battalions were transferred to other regular infantry regiments. The history of the 9th (County of London) Battalion is now embodied in that of 7th Battalion, The Rifles.
Credit for this entry to: Andrew Behan.