The following files in the National Archives were created by the Mercantile Marine department of the Board of Trade and relate to to First World War Prisoners of War.
| MT 9/951 | Seamen – Home (Code 122): “West Quarter” and “Riding” – Detained in Elbe – Owner’s liability for Crew Wages – Solicitor General’s Opinion> | 1914 |
| MT 9/962 | Prisoners of War (Code 106): Seamen – In Germany | 1914 |
| MT 9/1039 | Prisoners of War (Code 106): Repatriation – Seamen | 1916 |
| MT 9/1094 | Prisoners of War (Code 106): Seamen – Changes of address | 1917 |
| MT 9/1098 | Prisoners of War (Code 106): Seamen – Revised lists | 1916-1917 |
| MT 9/1101 | Prisoners of War (Code 106): Capt. Blaikie – “Caledonian” | 1916-1917 |
| MT 9/1127 | Prisoners of War (Code 106): “Eskimo” – Internment and repatriation of four seamen | 1917-1918 |
| MT 9/1130 | Prisoners of War (Code 106): “Cordova” – Changes of address | 1918 |
| MT 9/1133 | Prisoners of War (Code 106): Privileges – Mercantile Marine Officers | 1916-1918 |
| MT 9/1152 | Prisoners of War (Code 106): Royal Navy and Royal Naval Division personnel | 1918 |
| MT 9/1166 | Prisoners of War (Code 106): Payments to dependants of Merchant Navy personnel | 1915-1918 |
| MT 9/1176 | Prisoners of War (Code 106): Peace Conference – Points for discussion | 1918 |
| MT 9/1179 | Prisoners of War (Code 106): Crew of “Wordsworth” | 1918 |
| MT 9/1182 | Prisoners of War (Code 106): “Minnetonka” – Location of crew | 1918 |
| MT 9/1188 | Prisoners of War (Code 106): Leave – Prisoners in Holland | 1918 |
| MT 9/1190 | Prisoners of War (Code 106): Berne Agreement- Ratification by Turkish Government | 1916-1918 |
| MT 9/1196 | Prisoners of War (Code 106): Changes of address – Notification to shipowners | 1918 |
| MT 9/1197 | Prisoners of War (Code 106): “Wairuna” – Lists of crew | 1918 |
| MT 9/1199 | Prisoners of War (Code 106): Merchant Navy Officers – Wearing of uniform | 1918 |
| MT 9/1201 | Certificates of Competency (Code 15): Nautical School – Ruhleben P.O.W. Camp – Studies to count as sea time for Certificates | 1918 |
| MT 9/1207 | Prisoners of War (Code 106): J. C. West, Master “Antacus” – Request for confirmation of rating | 1917-1918 |
| MT 9/1208 | Prisoners of War (Code 106): Merchant Navy Officers and Navy Officers – Comparison of allowances to dependants | 1918 |
| MT 9/1211 | Prisoners of War (Code 106): Segregation – German Merchant Navy Officers | 1918 |
| MT 9/1227 | Prisoners of War (Code 106): Repatriation | 1914-1918 |
| MT 9/1230 | Awards (Code 6): Admiralty Awards – Enemy submarines, mines, etc. | 1915 |
| MT 9/1236 | Prisoners of War (Code 106): Repatriation – British and German Merchant seamen | 1917-1918 |
| MT 9/1238 | Prisoners of War (Code 106): Repatriation – Merchant seamen over 45 years of age | 1917-1918 |
| MT 9/1239 | Prisoners of War (Code 106): Merchant seamen released to Holland, U.K. or Switzerland | 1918 |
| MT 9/1240 | Prisoners of War (Code 106): Crews of “Jumna”, “Wordsworth” and “Turritella” | 1918 |
| MT 9/1241 | Prisoners of War (Code 106): Merchant Navy Officers – Certificates of rank | 1917-1918 |
| MT 9/1243 | Compensation (Code 25): Loss of effects – Merchant seamen repatriated from Camps in Germany | 1917-1918 |
| MT 9/1244 | Prisoners of War (Code 106): Ruhleben Camp – Changes | 1918 |
| MT 9/1245 | Prisoners of War (Code 106): Release of Merchant Navy Officers – Austria and Hungary | 1918 |
| MT 9/1249 | Prisoners of War (Code 106): Reports on visits to camps | 1916-1918 |
| MT 9/1253 | Prisoners of War (Code 106): Wages during internment | 1918 |
| MT 9/1257 | Wages (Code 146): Extra – Crews of vessels lost by war risk | 1917-1919 |
| MT 9/1259 | Prisoners of War (Code 106): Repatriation – Invalids | 1919 |
| MT 9/1260 | Prisoners of War (Code 106): Repatriation expenses | 1919 |
| MT 9/1266 | Prisoners of War (Code 106): Repatriation – Germans | 1919 |
| MT 9/1277 | Imperial Merchant Service Guild (Code 52): 24th, 25th and 26th Annual Reports | 1917-1919 |
| MT 9/1288 | Prisoners of War (Code 106): Return to U.K. | 1919 |
| MT 9/1301 | Prisoners of War (Code 106): Railway Fares on Repatriation | 1919 |
| MT 9/1307 | Prisoners of War (Code 106): Treatment – Board of Trade action | 1919 |
| MT 9/1312 | Prisoners of War (Code 106): Non-payment of wages – J. D. Martin | 1919 |
| MT 9/1324 | Prisoners of War (Code 106): Army Hospital Forms – Merchant seamen | 1919 |
| MT 9/1329 | Prisoners of War (Code 106): Wages during internment and expenses on repatriation | |
| MT 9/1366 | Mercantile Marine (Code 75): War History | 1916-1919 |
| MT 9/1427 | Prisoners of War (Code 106): Lascars – Compensation and allowances | 1915-1920 |
| MT 9/1444 | Prisoners of War (Code 106): Recovery of effects | 1920 |
| MT 9/1597 | Prisoners of War (Code 106): Treatment and Maintenance | 1917-1923 |
| MT 9/1906 | Prisoners of War (Code 106): Merchant Seamen – Status | 1929 |
| MT 9/1991 | Prisoners of War (Code 106): Lists – Request from International Transport Workers’ Federation | 1918-1930 |
| MT 9/1058 | Fryatt, Capt. Charles (Code 48): Execution | 1916 |
| MT 9/1066 | Fryatt, Capt. Charles (Code 48): Memorial | 1916 |
| MT 9/1411 | Deaths (Code 32): Prisoners of War in Turkey – List of burials | 1918-1920 |
| MT 9/1473 | Deaths (Code 32): Imperial War Graves Commission – Responsibility for Mercantile Marine graves. | 1921 |
| MT 9/1538 | Deaths (Code 32): Roll of Honour – Merchant seamen buried in Italy | 1922 |