Until about 2021 the Ministry of Defence (MoD) held all the Service Records for all service personnel who were discharged after about 1921. This covered those who served in World War 2 and the post-war period.
There used to be separate offices where the Service Records were held for the Royal Navy, the Army and the Royal Air Force. However, since about 2021 the MoD has been passing the Service Records for discharges prior to end of National Service (in 1963) to The National Archives (TNA).
Any requests for personnel discharged after 1963 should be addressed to the MoD see
www.gov.uk/government/collections/requests-for-personal-data-and-service-records
Thus, at the time of writing the situation regarding Post 1921 personnel is fluid as some records have not yet been transferred, some are pending cataloguing etc. at the TNA and others are now publicly available at the TNA. Furthermore the MoD and the TNA have different disclosure rules which means that the information available on a specific service member can be different depending upon which archive their record is currently with.
Royal Navy and Royal Marines
RN Officers (Commissioned and Warrant) – these are normally still with the MoD.
RN Ratings – If the subject enlisted in 1929 or after then their record will be with the MoD. Records for those enlisting before 1929 are probably publicly available.
RM Officers – If the subject was Commissioned after 1925 then their Service Record will be with the MoD. Those prior to this date are publicly available.
RN Other Ranks – Service Records for pre-1927 and post-1927 are at the TNA and the MoD respectively.
The following addresses may still be applicable for the RN and RM:
Director of Naval Career Management, Navy Search, TNT Archive Services, Tetron Point, William Nadim Way, Swadlincote, Derbyshire, DE11 OBB
For officers under the age of 60 in 2005 there was the Director of Naval Career Management, RESWO, Room 171, Victory Building, HMNB Portsmouth, PO1 3LS.
The British Army
Officers – These Service Records are currently still with the MoD.
Soldiers – These Service Records are usually available for pre-1963 discharges. Also, it is recommended that their Medal and Honours entitlements are checked and Unit Historical Records are probably available too.
Scots Guards – This Regiment retains their own records in their own Archive for both pre-1945 and post-1945 personnel. Therefore, it is necessary to contact the Regimental Archive.
https://scotsguards.org/archives/
Home Guard – The personnel records of Home Guard units have been recently transferred to the TNA (from the MoD). Currently, many of them are not yet catalogued or viewable at the TNA.
Women’s Land Army – See the section on this website under Genealogy > British Armed Forces
The following MoD address may still be applicable:
Army Personnel Centre, Kentigern House, 65 Brown Street, Glasgow, G2 8EX
Army Personnel Records, Ministry of Defence, Bourne Avenue, Hayes, Middlesex, UB3 1RS
The Foot Guards have an Archive and their address is Regimental Headquarters, The **** Guards, Wellington Barracks, Birdcage Walk, London, SW1E 6HQ (for **** insert the relevant Guards unit – Grenadier, Coldstream, Scots, Irish or Welsh).
Royal Air Force
Officers – The Service Records for Officers serving 1918-1922 are usually with the WW1 records and those for Officers serving after 1922 are still with the MoD.
Airmen – The records for those who served 1912-1939 are likely to be publicly available. This covers the Service Number range 1 to 562875. Those in the range 313001 to 316000 served with the Royal Navy and were then subsequently transferred to the Royal Naval Air Service before being transferred (again) to the RAF. The Service Records for Airmen whose Service Numbers are above 562875 are still with the MoD and they are in the process of being transferred to the TNA from the MoD.
RAF Innsworth used to hold the post WW1 Service Records but it closed in 2008. As far as the author is aware these Service Records were then passed to RAF Cranwell at
RAF Disclosures, Room 221B, Trenchard Hall, RAF Cranwell, Sleaford, Lincs, NG34 8HB
If you do find that this address is no longer valid please do inform me.