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UK military and Civil Service grades
A reference for non-military Allied staff on how UK military ranks and Ministry of Defence (MOD) Civil Service grades work, and how the two systems map to each other. Useful when reading email signatures, addressing officials in writing, and judging the level of authority a contact carries.
Star ranks (1★ to 4★)
"Star" ranks are the senior officer tier across the three services. They share the same NATO rank code (OF-6 to OF-9) but use different titles in the Royal Navy, Army, and Royal Air Force.
| Stars | NATO code | Royal Navy | Army | Royal Air Force |
|---|---|---|---|---|
| 1★ | OF-6 | Commodore | Brigadier | Air Commodore |
| 2★ | OF-7 | Rear Admiral | Major General | Air Vice-Marshal |
| 3★ | OF-8 | Vice Admiral | Lieutenant General | Air Marshal |
| 4★ | OF-9 | Admiral | General | Air Chief Marshal |
The single 5★ ranks (Admiral of the Fleet, Field Marshal, Marshal of the Royal Air Force) are largely ceremonial and rarely held in peacetime; they are not covered here.
Staff Officer grades (SO1, SO2, SO3)
SO1, SO2, and SO3 are role labels for officers in staff (headquarters, planning, policy) appointments — not separate ranks. The officer's substantive rank determines which SO band they fill.
| Role | NATO code | Royal Navy | Army | Royal Air Force |
|---|---|---|---|---|
| SO1 | OF-4 | Commander | Lieutenant Colonel | Wing Commander |
| SO2 | OF-3 | Lieutenant Commander | Major | Squadron Leader |
| SO3 | OF-2 | Lieutenant | Captain | Flight Lieutenant |
You will frequently see SO1/SO2/SO3 used in MOD email signatures and organograms instead of the substantive rank — for example, "SO1 Capability" rather than "Lt Col Capability".
MOD Civil Service grades
MOD civilians use the standard UK Civil Service grade structure. Senior Civil Service (SCS) grades are common counterparts in MOD-facing work; the lower delegated grades appear less often in partner-facing correspondence.
| Grade | Common job titles in MOD |
|---|---|
| AA | Administrative Assistant |
| AO | Administrative Officer |
| EO | Executive Officer |
| HEO | Higher Executive Officer |
| SEO | Senior Executive Officer |
| Grade 7 | Team leader / senior policy or technical lead |
| Grade 6 | Senior team leader / branch head |
| SCS Pay Band 1 | Deputy Director |
| SCS Pay Band 2 | Director |
| SCS Pay Band 3 | Director General |
| SCS Pay Band 4 | Permanent Secretary |
The Permanent Under-Secretary of State for Defence (PUS) is the most senior civilian in MOD and sits at SCS Pay Band 4.
Civilian–military equivalence
MOD applies a "broader defence working" alignment so that civilian and military staff can be compared by working level. Treat this as a guide to working-level equivalence, not formal seniority — appointments and decision authority can sit above or below grade.
| Civilian grade | Approximate military equivalent | Star / SO |
|---|---|---|
| EO | OR-6 (Sergeant / Petty Officer / Sergeant) | — |
| HEO | OF-1 / OF-2 (Lieutenant / Captain / Flying Officer / Flight Lieutenant) | SO3 (at OF-2) |
| SEO | OF-3 (Major / Lt Cdr / Sqn Ldr) | SO2 |
| Grade 7 | OF-4 (Lt Col / Cdr / Wg Cdr) | SO1 |
| Grade 6 | OF-5 (Colonel / Captain RN / Group Captain) | — |
| SCS Pay Band 1 (Deputy Director) | OF-6 | 1★ |
| SCS Pay Band 2 (Director) | OF-7 | 2★ |
| SCS Pay Band 3 (Director General) | OF-8 | 3★ |
| SCS Pay Band 4 (Permanent Secretary) | OF-9 | 4★ |
Using this in practice
- Reading signatures. "Maj A. Smith RE" is an Army Major (OF-3, SO2 in a staff post) in the Royal Engineers. "Gp Capt B. Jones" is an RAF Group Captain (OF-5, equivalent to Civil Service Grade 6).
- Pitching the right level. If you need a decision that commits resources, you are usually looking for Grade 7 / SO1 and above. Strategic or cross-MOD direction typically sits at SCS / star level.
- Forms of address. Default to the rank or grade title in writing ("Dear Brigadier", "Dear Director") unless the contact has signed off informally first.
- When in doubt. Ask the contact's office or a colleague who has worked with the post before — both services and MOD civilians are generally relaxed about this and will tell you.