Foreign Office correspondence in the period 1910-1919 was grouped in individually numbered files and then in one of a varying number of categories. These categories shared a single card index, now held at the National Archives in Kew, although records of the Foreign Office Library (FO 370), Chief Clerk's Department (FO 366), and of the wartime Foreign Trade Department (FO 833), are not included in the index.
Individual papers were identified in the card index by a country code, a paper number and a file number. These have to be translated to modern TNA references. Each country had its own code, composed of a unique stem number, to which could be added extra numbers or letters. This was done to indicate the category (now series) in which the papers were placed. For example, Germany had 18 for its stem number, so references to Germany in the card index may have the following codes:
|Category||Political||Commercial||Consular||Treaty||Africa to 1913|
|Series||FO 371||FO 368||FO 369||FO 372||FO 367|
|New codes added in...|
|Code||1118||18W or W 18||1218||N18||2118|
|Category||Contraband||War series in||Prisoners||News||Coal and tonnage|
|Series||FO 382||FO 371||FO 383||FO 395||FO 382|
P or Pr with an abbreviated country name denotes the Prize section in FO 372, the Treaty series.
2. The country code stem numbers
|Stem code||Country||Stem code||Country||Stem code||Country|
|1||Abyssinia to 1914; |
Africa from 1914
|4||Belgium and Congo||24||Liberia||44||Turkey|
|5||Bolivia from 1911||25||Maskat [Muscat]||45||United States of America|
|8||Central America (Guatemala, Honduras, Nicaragua)||28||Morocco||48||Zanzibar|
|10||China||30||Norway to 1914 |
Scandinavia from 1914
|50||General (W50N = War Miscellaneous News)|
|11||Colombia||31||Pacific Islands to 1913||51||America: General from 1912|
|12||-||32||Panama and Costa Rica||52||Contract Labour from 1914|
|13||Crete to 1913||33||Paraguay||53||Albania 1914-1916|
|14||Cuba||34||Persia||54||Ecuador from 1914|
|15||Denmark||35||Peru (includes Bolivia to 1910 and Ecuador to 1913 )||55||Poland from 1918|
|16||Egypt||36||Portugal||56||Finland from 1918|
|17||France||37||Roumania [Romania]||57||Siberia from 1918|
|18||Germany||38||Russia||58||Caucasus from 1918|
|19||Greece to 1914 |
Balkans from 1914
|39||Serbia to 1914 |
War from 1914
|59||Baltic State 1919 only|
|20||Hayti [Haiti]and San Domingo||40||Siam||-||-|
3. The card index
Step 1: Understanding the cards: some examples
|15||Luggage detained in Germany|
[Code 1218 = Prisoners, Germany FO 383]
|19||Situation at Rowanduz|
[Code W34 = Persia, War Series in FO 371]
|1117||F1210173||15||Arrest in France for trading with the enemy|
[Code 117 = Contraband, France, FO 382]
Remember when identifying the file number that the lowest number, or that which appears below another number is usually the file number. When file and paper number are the same, the whole file is relevant. Some subjects have cross-references on the first card entry.
Step 2: The Catalogue
Use the code to identify which series you need. Then search the series list by country, date and range of file numbers. This should give you the piece number with which to order the file.
4. No file number given on the card?
If cards do not give file numbers, look at the catalogue to find the relevant register of general correspondence in FO 566. The correspondence of most of the wartime departments can be accessed in this way. At the appropriate date cut in the register, search the column second from left on the left page for the paper number. Then, the number in the 'kept with' column on the right of that page indicates the file with which the paper was kept. Refer to the relevant series list, according to country/subject code and letter prefix (if present), to trace the file.
References to related material may appear in the register. Left hand pages of registers refer to incoming correspondence and right hand pages to outgoing. Entries in black in the 'forward reference' file refer to incoming correspondence arranged numerically on the left page. Entries in red refer to outgoing correspondence arranged numerically on the right page.
5. 1920 papers
Reforms of 1920 led to the introduction of a new registry and alpha-numerical filing system, and to a new correspondence index. Their application to various departments was staggered throughout 1920. Consequently, 1920 material can be found by using either the card index or the new registers and printed indexes.
6. Further reading
Michael Roper, The records of the Foreign Office, 1782 - 1968 (Public Record Office Publications, 2002)
L Atherton, 'Never Complain, Never Explain', Records of the Foreign Office and State Paper Office 1500-c.1960, Public Record Office Readers' Guide No. 7 (PRO publications, 1994)
The Records of the Foreign Office, 1782-1939, Public Record Office Handbooks No. 13 (HMSO, 1969)