Question to the Foreign, Commonwealth & Development Office:

To ask the Secretary of State for Foreign and Commonwealth Affairs, whether the jurisdiction of any seas in the northern and southern maritime borders of the UK and the Republic of Ireland have been exchanged in the last 10 years.

The Agreement between the Government of the United Kingdom of Great Britain and Northern Ireland and the Government of Ireland establishing a Single Maritime Boundary between the Exclusive Economic Zones (EEZ) of the Two Countries and parts of their Continental Shelves was presented to Parliament in June 2013 (Cm 8666) and subsequently came into force on 31 March 2014 (Treaty Series No. 21 (2014)).

The Explanatory Memorandum presented to Parliament alongside Cm 8666 stated that the Agreement firstly amended the existing delimited continental shelf boundary between the UK and Ireland as defined in a 1988 Agreement, a supplementary Protocol of 1992 and an Exchange of Notes of 2001. The effect of the amendment was to transfer part of what was previously Irish Continental Shelf to the UK, in exchange for an area of the UK's Continental Shelf. In amending the existing Continental Shelf boundary the 2014 Agreement superseded both the 1988 Agreement and the 2001 Exchange of Notes, which were terminated.

The Agreement then provides for the coordinates of the amended Continental Shelf boundary, up to 200 nautical miles, to delimit also the EEZ boundary between the two states.

In negotiating to align a new EEZ boundary with the existing Continental Shelf boundary it was discovered that there were two small areas on the Irish side of the boundary that were more than 200 nautical miles from Irish baselines on their coast. As these could not be incorporated into an Irish EEZ, it was agreed to swap these two areas of Irish Continental Shelf for areas of the UK's Continental Shelf, the areas being of equal size and potential exploitability e.g. for the purposes of hydrocarbons and fisheries.