The negotiations behind Great Britain’s exit from the European Union have run into a critical delay as a Northern Ireland party has pulled out of an agreement regarding the future border between the United Kingdom and Ireland.

This sudden decision by the Northern Irish party has left British Prime Minister Theresa May in a state of surprise as talks with the European Union in Brussels reach a standstill. This news comes as a draft deal between the Britain and the EU was being planned to allow Brexit negotiations to advance to the next stage.

The decision has set back Mrs. May in achieving a much desired breakthrough in talks with the European Union who have increasingly appeared to have an advantage in negotiations. As Britain tries to undo more than 40 years of its partnership with the EU this news highlights for some the weakness of Prime Minister May.

Critics of May and of the Brexit negotiations take this news as further evidence that Britain should just remain in the European Union. The notion of an “exit from Brexit” is becoming increasingly popular in British political circles.

The three major issues facing Brexit negotiations take the form of Britain’s outstanding debts to other EU nations, the protection of EU citizens within Britain and the status of the Irish border. As the Republic of Ireland will remain in the EU, this recent news presents a significant barrier to further Brexit talks.

Prime Minister May has already agreed to large concessions on two of these issues. Britain last week agreed pay 47 to 53 billion USD in a divorce settlement to the European Union. Britain was also expected to agree that the European Court of Justice would have the primary responsibility of deciding the rights of EU citizens remaining after Brexit took place.

Following these concessions, the question of Ireland was then brought to the forefront. Compromises were drafted to allow Northern Ireland to retain some of the benefits of being in the EU while still technically leaving with the rest of Britain.

This decision was designed to minimise the impact a hard land border between Britain and the EU existing in Ireland. Critics believe that the creation of a hard border between Northern Ireland and The Republic of Ireland could revitalise historic violence between the two states.

For fear of enabling the creation of a United Ireland, there have been British arguments not to confer and special rights to Northern Ireland. Regardless the pulling out of Northern Island from existing agreements means an uphill battle for the realisation of Brexit.