„Protecting the Good Friday Agreement is essential,“ Martin said. In 1922, the newly created United Kingdom and the Land of Bavaria concluded an agreement on the Common Travel Area (CTA). This gave British and Irish citizens the right to travel, live and work in both jurisdictions. Passport controls are not used to travel between them. The free movement provisions resulting from EU membership replaced them to some extent, but the parties kept their bilateral agreement alive when it did not have treaty status. In 2011, the British and Irish governments informally agreed to continue their joint controls upon entry of non-EEA nationals into the CTA.  Britain will annihilate the Brexit agreement and the Irish border with the European Union, which may well have the consequences of a return to a hard border between Northern Ireland and the Republic of Ireland. The border reaches the sea at two coves: Lough Foyle to the northwest and Carlingford Lough to the east. In the century since Ireland`s independence, she and the United Kingdom have never defined where the border is in these canals. Both bays are recovered by boats from both nations.  During Britain`s accession to the EU, there was no need to resolve the problem, given that the Common Fisheries Policy (CFP) allowed all EU Member States to fish in the waters of other countries and neighbouring countries still had the right to fish on the coasts of the other party within 12 nautical miles.  The EU and the UK have an informal trade agreement with Northern Ireland after Brexit and its land borders with the EU.
The agreement is not bound by the latest trade negotiations, but could help put the wheels in the right way. As far as Brexit is concerned, a „hard border“ means a limited number of authorized (and physically controlled) crossing points, occupied by customs officers and police and supported by military personnel in times of tension.  Drivers of vehicles crossing the vehicle must report goods during transport, commercial carriers must submit bill of lading and prove that the goods meet the minimum standards of the area concerned. Tariffs (in the form of tariffs) may be due.  This was the position at the border between 1923 and the Single European Act of 1993.  (In this context, a „hard border“ does not mean a fortified border, but during the unrest British security forces blocked many unauthorized crossing points for security reasons.