The „backstop“ would have required northern Ireland to remain in certain aspects of the internal market until an alternative agreement between the EU and the UK is concluded. The proposal also provided that the UK as a whole would have a common customs territory with the EU until a solution was found to avoid the need for customs controls in the UK (between Northern Ireland and Great Britain). The „backstop“ element was that if the UK and the EU did not agree on another agreement, for example on a trade agreement between the UK and the EU at the end of the transition period, the agreement could continue to apply indefinitely. On 10 October 2019, Mr Johnson and Leo Varadkar held „very positive and promising“ talks that led to the resumption of negotiations and a week later Mr Johnson and Jean-Claude Juncker announced that they had agreed (subject to ratification) on a new withdrawal agreement replacing the backstop with a new protocol on Northern Ireland.2  Under the protocol, Northern Ireland will continue to apply EU customs legislation and comply with its product standards rules (the so-called internal market for products). The Northern Ireland Protocol Command Document provides additional details on the fundamental principles and the work of the UK Government to implement the protocol and assist businesses that have come into force. This document was presented to Parliament on 10 December. The protocol was also rejected by the Ulster Unionist Party and the Traditional Unionist Voice.  The concept of „hard border“ is defined by „physical infrastructure and control,“ as stated in the preamble to the protocol on page 303: in the following months, the British Parliament has refused three times to ratify the agreement. In July 2019, Boris Johnson became Prime Minister of the United Kingdom and leader of the Conservative Party. On 28 August 2019, the Johnson government refused to negotiate with Brussels unless the backstop was abolished, which the EU would not do.
 The Republic of Ireland is the second highest per capita domestic product in the EU after Luxembourg, thanks to a favourable corporate tax system and membership of the European single market.  About 85% of Ireland`s freight exports worldwide are from ports in the UK, about half of which are destined for the UK, while half continue to the EU via Dover and Calais.  The UK`s use as a „land bridge“ is rapid (it takes 10.5 hours for the Dublin-Holyhead-Dover-Calais route), but could be compromised by customs checks in Wales and Calais in a Brexit without agreement.