evidence: Local and geographic effects [edit]The potential impact on the border between Northern Ireland and the Republic of Ireland has been a contentious issue. Since 2005, the border had been essentially invisible.[271] After Brexit, it became the only UK–EU land border[272] (not counting the land borders that EU states Spain and Cyprus have with British Overseas Territories). All involved parties agreed a hard border should be avoided,[273] because it might compromise the Good Friday Agreement that ended the Northern Ireland conflict.[274][275][276] To forestall this, the EU proposed a "backstop agreement" that would keep the UK in the Customs Union and keep Northern Ireland in some aspects of the Single Market until a lasting solution was found.[277] The UK Parliament rejected this proposal. After further negotiations in autumn of 2019, an alternative model, the Ireland/Northern Ireland Protocol was agreed between the UK and the EU. Under the Protocol, Northern Ireland is formally outside the EU single market, but EU free movement of goods rules and EU Customs Union rules still apply; this ensures there are no customs checks or controls between Northern Ireland and the rest of the island.