Mobile Naval Base Defence Organisation No. 1
Present at North African landings in WW2. Present at Sicily landings. Present at Anzio.
Present at Normandy. Believed composed of mainly Hostilities Only Royal Marine Commandos during WW2. Utilised for beach defence role following assaults on defended positions. Composed of Bofors AA guns and other weapons.
Originally formed in 1923 at Fort Cumberland.
The MNBDO groups were essentially a royal marine base component of the larger Royal Naval part of beach landings.
MNBDO I: Formed September 1939 for defence of Naval bases. Disbanded September 1944.
MNBDO II: Formed January 1941. Disbanded May 1944.
Fortress Unit I: Formed August 1939 as defence units to install and man guns for Scapa Flow and other Naval bases they also served in Iceland. Disbanded January 1941 when absorbed into MNBDO II.
Fortress Unit II: Formed May 1940.
Special Gun-mounting Party, RM: Formed 27/8/1939 to install coastal defence guns around major ports, including Yarmouth.
3 Mobile Naval Base Brigade: Formed Summer 1943 to defend against Japanese amphibious and other raids on naval bases in Ceylon. Disbanded 14/5/1944, personnel remustered for Landing Craft crews.
'MNB Group' with XXXIII Indian Corps: 1 RM AA Brigade HQ and 1st RM (Heavy) AA Regiment (and L & M Unit) from MNBDO I were sent to India from Ceylon in April 1943. Disbanded in January 1944.