Prior to Cypriot accession to the EU in 2004, although the United Kingdom was an EU member at the time, EU law did not apply to the sovereign base areas. This protocol applied EU law relating to the Common Agricultural Policy, customs, indirect taxation, social policy and justice and home affairs to the sovereign base areas. The sovereign base areas' authorities also made provision for the unilateral application of directly applicable EU law. The UK also agreed in the Protocol to keep enough control of the external (i.e. off-island and northern Cyprus) borders of the base areas to ensure that the border between the sovereign base areas and the Republic of Cyprus could remain fully open and would not have to be policed as an external EU border. Consequently, the sovereign base areas would have become a "de facto" part of the Schengen Area if and when Cyprus implemented it. The base areas are already "de facto" members of the eurozone due to their previous use of the Cypriot pound and their adoption of the euro as legal tender from 2008.