After the Second World War the British Army had fourteen infantry depots, each bearing a letter. The depots were territorially organised, and Infantry Depot L at Brecon was the headquarters for the county regiments of Wales and Monmouthshire.
In 1948, the depots adopted names and this depot became the Welsh Brigade, with all regiments being reduced to a single battalion at the same time. The Welsh Brigade was formed on 14 July 1948 combining the depots of three regiments:
- Messenger, Charles. "A History of British Infantry: For Love of Regiment, Volume 2, 1915-1994". p. 156.
- Whitaker's Almanack 1956, p. 471
- "Welsh Infantry Brigade Depot". 8 May 1958. Retrieved 18 April 2014.
- Whitaker's Almanack 1969, p. 473