The regiment was still in Norway on 15 November 1945 when 638 Rgt began the process of entering suspended animation, completing the process on 13 December. Following the end of hostilities most territorial artillery regiments had been placed in suspended animation by late 1946. On 1 January 1947 most of these regiments were reconstituted and many new regiments were formed as part of the reformed and re-organised TA, with new numbers according to the renumbering plan for the complete re-designation of all RA units, both regular and territorial. In accordance with this, the light anti-aircraft (LAA) regiments were assigned numbers between 512 and 588. The 5th Btn was reformed as 588th (Royal Northumberland Fusiliers) Light Anti-Aircraft Regiment, Royal Artillery, and followed the new standard RA organisation, which consisted of RHQ, P, Q, and R Batteries, all of which were based in Walker on Tyne. The regiment provided the LAA component of the TA's 50th (Northumbrian) Infantry Division. On 1 September 1950 the regiment was converted back to infantry and simultaneously merged with the 4th Btn to form the 4th/5th Battalion, The Royal Northumberland Fusiliers. In 1967 the battalion's Territorial and Army Volunteer Reserve (TAVR) successors were A (Royal Northumberland Fusiliers) Company, Fusilier Volunteers and the 4th/5th/6th (Territorial) Battalion, Royal Northumberland Fusiliers both of which were eventually expanded into the 6th (Northumberland) Battalion, The Royal Regiment of Fusiliers. The Northumberland TA successors are currently part of 'X' and 'Z' companies in the 5th (Volunteer) Battalion, The Royal Regiment of Fusiliers. Commanding Officers  Those commanding officers which served during World War I:  "1/5th Battalion"   "2/5th Battalion"   "3/5th (5th Reserve) Battalion"   Honorary Colonels  The battalion's (later regiment's) Honorary Colonels included: