The completion of the European single market in 1992 (initiated by European Commissioner Lord Cockfield) and the Good Friday Agreement (negotiated by Irish-American Senator Mitchell) in 1998 were seen as possible to dismantle the previously extensive border infrastructure between Northern Ireland and the Republic of Ireland. [8] The Northern Ireland Protocol replaces the previous plan known as the Irish backstop, negotiated by former British Prime Minister Theresa May. In October 2019, UK and EU negotiators agreed on a revised protocol (see below) that resolved many of these issues by getting Northern Ireland to leave the EU de jure, but with a de facto border between the islands (Ireland and the UK). After the 2016 referendum, the Irish backstop was negotiated with the European Union by former Prime Minister Theresa May.