# What did MI-1 through MI-4 do?

**URL:** <https://boards.straightdope.com/t/what-did-mi-1-through-mi-4-do/192730>\
**Category:** Factual Questions\
**Created:** [August 3, 2003, 4:41pm UTC](https://boards.straightdope.com/t/what-did-mi-1-through-mi-4-do/192730 "2003-08-03T16:41:10Z")\
**Posts on this page:** 5\
**Page:** 1

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**Author:** ![SuaSponte](https://avatars.discourse-cdn.com/v4/letter/s/67e7ee/32.png) [@SuaSponte](https://boards.straightdope.com/u/SuaSponte)\
**Post date:** [August 3, 2003, 4:41pm UTC](https://boards.straightdope.com/t/what-did-mi-1-through-mi-4-do/192730/1 "2003-08-03T16:41:10Z")

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It is my understanding that the acronyms MI-5 (now the Security Service) and MI-6 (now the SIS) stood for British Military Intelligence - Sections 5&6. That implies that there were/are Sections 1 through 4. Are/were there, and what did they do?

Sua

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**Author:** ![bibliophage](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/bibliophage/32/7615_2.png) [@bibliophage](https://boards.straightdope.com/u/bibliophage)\
**Post date:** [August 3, 2003, 5:01pm UTC](https://boards.straightdope.com/t/what-did-mi-1-through-mi-4-do/192730/2 "2003-08-03T17:01:36Z")

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At least some of them existed. Other than MI5 and MI6, I’m not sure if any of them still exist. According to the _Encyclopedia of Espionage_ by Norman Polmar and Thomas B. Allen, they were:

MI1 Directorate of Military Intelligence  
MI1(b) Cryptanalysis Section  
MI1© Foreign Section  
MI3 European Country Section  
MI3(b) German sub-section (became MI14 in 1940)  
MI5 Security Service  
MI6 Security Intelligence Service  
MI8 Radio Security Service  
MI9 Escape and Evasion Service  
MI14 German Section  
MI19 Combined Serviced Detailed Interrogation Centre  
MI(L) War Office Liaison with Allied Intelligence Services.

There are still some gaps here. 2, 4, 7, 10-13, and 15-18. I guess if they told you, they’d have to kill you.

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**Author:** ![johncole](https://avatars.discourse-cdn.com/v4/letter/j/5f9b8f/32.png) [@johncole](https://boards.straightdope.com/u/johncole)\
**Post date:** [August 3, 2003, 6:10pm UTC](https://boards.straightdope.com/t/what-did-mi-1-through-mi-4-do/192730/3 "2003-08-03T18:10:55Z")

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From [**Guardian Unlimited - Notes & Queries**](http://www.guardian.co.uk/notesandqueries/query/0,5753,-20949,00.html) we have:

> [@](#):
>
> MI (Military Intelligence) had agencies numbered up to 19, but not all at the same time. Most were folded into MI5, MI6 or GCHQ after the war. I’ve found the following after a few web searches: MI1 (Codebreaking), MI2 (Russia and Scandinavia), MI3 (Eastern Europe), MI4 (Aerial Reconnaisance), MI8 (Military Communication Interception), MI9 (Undercover operations), MI10 (Weapons analysis) MI14 and MI15 (German specialists), MI19 (PoW debriefing), MI17 (Military Intelligence “Head Office”). Conspiracy theorists will have you believe that there is still a clandestine MI7 dealing with matters extraterrestrial.

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**Author:** ![SuaSponte](https://avatars.discourse-cdn.com/v4/letter/s/67e7ee/32.png) [@SuaSponte](https://boards.straightdope.com/u/SuaSponte)\
**Post date:** [August 5, 2003, 7:45pm UTC](https://boards.straightdope.com/t/what-did-mi-1-through-mi-4-do/192730/4 "2003-08-05T19:45:22Z")

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I note there are differing descriptions for some of the agencies, e.g. MI3 and MI9.

I suspect disinformation. 😃

Sua

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**Author:** ![Fuji\_Kitakyusho](https://avatars.discourse-cdn.com/v4/letter/f/f0a364/32.png) [@Fuji\_Kitakyusho](https://boards.straightdope.com/u/Fuji_Kitakyusho)\
**Post date:** [August 6, 2003, 10:06am UTC](https://boards.straightdope.com/t/what-did-mi-1-through-mi-4-do/192730/5 "2003-08-06T10:06:28Z")

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> [@](#):
>
> \*Originally posted by johncole \*  
> \*\*Conspiracy theorists will have you believe that there is still a clandestine MI7 dealing with matters extraterrestrial. \*\*

MI3 looks a lot like MiB. Coincidence?..