At the end of the Crimean War in 1856 a declaration was issued to abolish privateering. In effect, it was something many powers were adhering to already, and was readily signed by numerous states including the United Kingdom, Austria-Hungary, France, Prussia, Russia, Sardinia and the Ottoman Empire. It did, however, mark the first attempt by several powers to officially enforce maritime law in times of war.
Two of its key points were:
- The neutral flag covers enemy's goods, with the exception of contraband of war;
- Neutral goods, with the exception of contraband of war, are not liable to capture under enemy's flag.
What it didn’t seem to do, however, was make any reference to what was considered to be contraband of war. Specifically, was coal included? Denmark certainly thought so, and in the Franco-Prussian War, refused to allow the French Navy to coal at Kïoge.
This left Britain with a huge problem. There was a paucity of Coaling Stations in some areas mainly due to the ad hoc nature of their acquisition and establishment, many being spoils of the Napoleonic Wars. As the Royal Navy could habitually use foreign stations in peacetime, the Admiralty had made little attempt to rectify this situation. For example, on the route around the Cape, the Royal Navy regularly used Lisbon, Madeira and the Cape de Verde Islands to coal. As most ships could only steam for 3,000 miles, the reports suggested a war would present extreme difficulties for coaling the fleet, and thus protecting British interests in some key places.. If British ships could not coal in neutral ports, as they did in peacetime, then they would need to establish a coherent plan as to where they would coal in war.
This problem was discussed by the Carnarvon Commission, which looked into coaling station defence and the provision of coal in war. The report states that because of the Declaration, ‘the supply of coal to belligerents in the ports of neutral States is regulated by the laws of those States subject only to the condition that a neutral State must give equal facilities to all belligerents.’ Thus, it was not unlikely that Britain could be denied coal at coaling stations they regularly used in peacetime. It then goes on to warn that of the forty-seven stations now in use by Royal Navy ships, twenty-six were in foreign territory, so could not be counted on in war. The situation seemed bleak, but Britain still had more coaling stations than any other power, although they also had far more interests outside Europe. Even so, a foreign power would find it difficult to conduct naval warfare on a wide scale without using neutral coal.
The reports go on, however, to suggest how a power might do so. ‘Rules... would not prevent a belligerent ship from obtaining a full supply of coal in a neutral port... It is, moreover, difficult to enforce the rules; and it is doubtful whether the ships of a strong naval Power would submit to their operations being crippled for want of coal by the regulations of a small State in a distant port.’
If this was the case, it makes it difficult to understand why Britain was so worried about coaling at a neutral port, being the strongest naval power of them all. Perhaps the Commissioners were looking to a worst case scenario, or assuming some sort of moral high ground, but it is hard to imagine that Britain would not coal at neutral ports if its enemy was to.
 Friedrich Wilhelm Rüstow, The War for the Rhine Frontier 1870; Its Political and Military History. , trans. J. L. Needham, vol. III (Edinburgh, 1871, 1872)
 Willock, Bulwark of Empire : Bermuda's Fortified Naval Base, 1860-1920. 1-3
 CO 537/208
 Vice Admiral P H Colomb, Coaling Stations and Their Relations to Our Trade Routes’, (British Library, BL. C.193 a.257 1893)
 Summary of Carnarvon Reports, PRO 30/6/131