Forum of adoption: Diplomatic Conference
In force: no
Entry into force: 14.09.1937
During the Spanish Civil War, nine Powers agreed to take collective measures to suppress attacks by submarines against merchant vessels. The Agreement refers in the preamble to the provisions of the London Treaty of 1930 and the procès-verbal of 1936 concerning submarine warfare. In the Supplementary Agreement of 17 September 1937 the same Powers made the principles of the first Agreement applicable to attacks by surface vessels and aircraft.
Meetings of forum; 09.09.1937 – 14.09.1937, Nyon
Date of adoption: 14.09.1937
Number of articles: 9
Authentic textEnglish; French
Source D.Schindler and J.Toman, The Laws of Armed Conflicts, Martinus Nihjoff Publisher, 1988, pp.887-889.
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Whereas arising out of the Spanish conflict attacks have been repeatedly committed in the Mediterranean by submarines against merchant ships not belonging to either of the conflicting Spanish parties; and
Whereas these attacks are violations of the rules of international law referred to in Part IV of the Treaty of London of 22 April 1930, with regard to the sinking of merchant ships and constitute acts contrary to the most elementary dictates of humanity, which should be justly treated as acts of piracy; and
Whereas without in any wily admitting the right of either party to the conflict in Spain to exercise belligerent rights or to interfere with merchant ships on the high seas even if the laws of warfare at sea are observed and without prejudice to the right of any participating Power to take such action as may be proper to protect its merchant shipping from any kind of interference on the high seas or to the possibility of further collective measures being agreed upon subsequently, it is necessary in the first place to agree upon certain special collective measures against piratical acts by submarines:
In view thereof the undersigned, being authorized to this effect by their respective Governments, have met in conference at Nyon between the 9 and the 14 September 1937, and have agreed upon the following provisions which shall enter immediately into force:
I. The participating Powers will instruct their naval forces to take the action indicated in paragraphs II and III below with a view to the protection of all merchant ships not belonging to either of the conflicting Spanish parties.
II. Any submarine which attacks such a ship in a manner contrary to the rules of international law referred to in the International Treaty for the Limitation and Reduction of Naval Armaments signed in London on 22 April 1930, and confirmed in the Protocol signed in London on 6 November 1936, shall be counter-attacked and, if possible, destroyed.
III.The instruction mentioned in the preceding paragraph shall extend to any submarine encountered in the vicinity of a position where a ship not belonging to either of the conflicting Spanish parties has recently been attacked in violation of the rules referred to in the preceding paragraph in circumstances which give valid grounds for the belief that the submarine was guilty of the attack.
IV. In order to facilitate the putting into force of the above arrangements in a practical manner, the participating Powers have agreed upon the following arrangements:
1. In the western Mediterranean and in the Malta Channel, with the exception of the Tyrrhenean Sea, which may form the subject of special arrangements, the British and French fleets will operate both on the high seas and in the territorial waters of the participating Powers, in accordance with the division of the area agreed upon between the two Governments.
2. In the eastern Mediterranean,
(a) Each of the participating Powers will operate in its own territorial waters;
(b) On the high seas, with the exception of the Adriatic Sea, the British and French fleets will operate up to the entrance to the Dardanelles, in those areas where there is reason to apprehend danger to shipping in accordance with the division of the area agreed upon between the two Governments. The other participating Governments possessing a sea border on the Mediterranean undertake, within the limit of their resources, to furnish these fleets any assistance that may be asked for; in particular, they will permit them to take action in their territorial waters and to use such of their ports as they shall indicate.
3. It is further understood that the limits of the zones referred to in sub-paragraphs I and 2 above, and their allocation shall be subject at any time to revision by the participating Powers in order to take account of any charge in the situation.
V. The participating Powers agree that, in order to simplify the operation of the above-mentioned measures, they will for their part restrict the use of their submarines in the Mediterranean in the following manner:
(a) Except as stated in (b) and (c) below, no submarine will be sent to sea within the
(b) Submarines may proceed on passage after notification to the other participating Powers, provided that they proceed on the surface and are accompanied by a surface ship.
(c) Each participating Power reserves for purposes of exercises certain areas defined in Annex I hereto in which its submarines are exempt from the restrictions mentioned in (a) or (b).
The participating Powers further undertake not to allow the presence in their respective territorial waters of any foreign submarines except in case of urgent distress, or where the conditions prescribed in sub-paragraph (b) above are fulfilled.
VI. The participating Powers also agree that, in order to simplify the problem involved in carrying out the measures above described, they may severally advise their merchant shipping to follow certain main routes in the Mediterranean agreed upon between them and defined in Annex II hereto
VII. Nothing in the present agreement restricts the right of any participating Power to send its surface vessels to any part of the Mediterranean.
VIII. Nothing in the present agreement in any way prejudices existing international engagements which have been registered with the Secretariat of the League of Nations.
IX. If any of the participating Powers notifies its intention of withdrawing from the present arrangement, the notification will take effect after the expiry of thirty days and any of the other participating Powers may withdraw on the same date if it communicates its intention to this effect before that date.
Done at Nyon, this fourteenth day of September nineteen hundred and thirty-seven, in a single copy, in the English and French languages, both texts being equally authentic, and which will be deposited in the archives of the Secretariat of the League of Nations.