maritime boundaries between France and U.K(Great Britain and northern Ireland)

The border between the countries of France and the United Kingdom in Europe is a border that stretches along the Channel, the North Sea, the Atlantic Ocean (maritime border) and the Channel Tunnel (land border). It is defined by several international arbitrations from 1977, 1978, 1982, 1988 and 1991 for the maritime border and by the Treaty of Canterbury (1986) for the land border.

The Anglo-French continental shelf boundary through the English Channel was achieved through arbitration between the parties. The role of islands was crucial in this case – particularly the impact of the UK’s Channel Islands located on the “wrong” side of a median line between the two states’ mainland coasts. Were these islands to be accorded full effect in delimiting a median line, France would have been restricted to only a small proportion of the continental shelf in the central part of the Channel. The Court of Arbitration, in its decision of 30 June 1977, resolved this problem by semi-enclaving the Channel Islands, which are now fully enclaved thanks to bilateral Anglo-French agreements concerning Guernsey (1992) and Jersey (2000).

The parties also disputed the UK’s use of Eddystone Rock as basepoint. The Court of Arbitration found that Eddystone Rock was indeed a valid basepoint less on the basis of the geographical and legal characteristics of the feature itself, and more on the basis that France had accepted its use as a basepoint in the delimitation of fisheries limits and had thus acquiesced to its status as a valid basepoint. Finally, the potential impact on the Scilly Islands on the final, seaward, part of the boundary extending southwestwards represented a problematic issue. This problem was resolved through awarding these islands a half-effect. Although technical problems were encountered in relation to the final section of the boundary out to its terminus on the 1,000 m isobath, it remains in force.