Summary and Background Terminology describing marine areas Territorial Sea
26.The UK territorial sea is defined by the Territorial Sea Act 1987 as the sea extending 12nm from the baseline. For the most part the territorial sea of the UK does not adjoin that of any other state. Where it does do so in the English Channel, the Territorial Sea (Limits) Order 1989 (SI 1989/482) sets out the limits of the territorial sea in the Straits of Dover in accordance with an agreement between the UK and France. In relation to the delineation of the territorial sea between the UK and the Republic of Ireland, the situation is more complex, with no boundary having been agreed between the two states. Instead arrangements have been put in place under the Belfast Agreement for joint management of the Loughs that form the border (the Foyle, Carlingford and Irish Lights Commission’s Loughs Agency).
27.Within the territorial sea, the UK has jurisdiction for the sea itself, the seabed subjacent and the air above. This is subject to the right of innocent passage by ships of all other states.
28.Parts of the UK territorial sea form part of Scotland, Northern Ireland and Wales for the purpose of exercising devolved functions. The Scotland Act 1998 defines “Scotland” as including so much of the internal waters and territorial sea of the United Kingdom as are adjacent to Scotland (section 126(1)). Similarly, section 98 of the Northern Ireland Act 1998 defines Northern Ireland as including so much of the internal waters and territorial sea of the United Kingdom as are adjacent to Northern Ireland. The Government of Wales Acts 1998 and 2006 provide that “Wales” includes the sea adjacent to Wales out as far as the seaward boundary of the territorial sea (see section 158(1) of the 2006 Act). The extent of the “English” territorial sea is normally assumed to be that part of the territorial sea that has not been assigned to another part of the United Kingdom but was defined in section 32M of the Electricity Act 1989, inserted by section 37 of the Energy Act 2008.