Emma de Souza has announced she is withdrawing her legal appeal after a three-year court battle to be recognised by the Home Office as Irish under the Good Friday Agreement (GFA).
It comes after Mrs De Souza and her husband Jake secured a concession from the Home Office last week that British and Irish citizens born in Northern Ireland will be treated as EU citizens for immigration purposes.
As a result the Home Office will no longer force people to renounce British citizenship in order to access rights to which they are entitled and will instead accept the people of Northern Ireland can identify as British, Irish or both.
However, the changes are only temporary as any third country national who wishes to apply for settled status will only have until June 2021 to do so, the date the EU settlement scheme closes.
The couple had appealed to the Court of Appeal in Northern Ireland after a ruling that people born in Northern Ireland were automatically British citizens under law.
"When we began this legal challenge it was on the grounds that I, an Irish citizen born in Northern Ireland, should be entitled to the same rights and entitlements as all other Irish and EU citizens in the UK and that my right under the GFA to be accepted as Irish should be respected by the Home Office.
"The Home Office now accept our argument and has conceded that principle," Mrs De Souza said during a press conference on Thursday morning.
The changes to the immigration rules whilst enormously welcomed and beneficial to many do not fully address all the underlying issues plaguing this region.Emma de Souza
The changes conceded by the Home Office will allow the Derry woman's US-born husband to remain in the UK on the basis of his wife's Irish citizenship.
The campaigner said the foundation of her legal complaint had been conceded by the British Government, therefore the couple had no choice but to withdraw their legal appeal, which was due to be heard next month.
"We have been left with no other option," she said.
"We know that many will be disappointed by this news as our work to address the inconsistencies in the implementation of legislation from the GFA has highlighted that there is so much more at stake here than just the changes we achieved in our case.
"We recognise and share in your disappointment. The changes to the immigration rules whilst enormously welcomed and beneficial to many do not fully address all the underlying issues plaguing this region.
"The British Government has failed to give domestic legal effect to the birthright provisions of the GFA and continue to automatically confer British citizenship on all the people of NI, even if they identify as Irish."
Jake De Souza added: "This disappointment however, should not overshadow what is an unbridled win worth celebrating. Families have and will continue to be reunited thanks to these changes and everyone in NI will benefit from the government's recognition of the rights provided under the GFA.
"It is the families being forced apart which inspired us to keep going well after my own residence was secured. We wanted to be the last people the government would be allowed to deny their rights before someone made them accountable. The people of NI deserve better and after 20 years of mistreatment, are another step closer."
Mrs De Souza said the couple will continue the "We Are Irish Too" campaign in order to push for what they say is "full implementation of the GfA", including the right to identify and British, Irish or both.
It is so important that you have achieved your win around the basis of people identifying as British, Irish or both and crucially as they so choose.SDLP MP Claire Hanna
She added: "Going forward we will continue to work with political parties across NI, civil society and rights organisations, along with the Irish government as well as members of Congress in the United States with the help of the Ad Hoc committee to protect the GFA so that we can see the work of the GFA complete. We are not giving up."
SDLP MP Claire Hanna, speaking during the press conference, said: "It is so important that you have achieved your win around the basis of people identifying as British, Irish or both and crucially as they so choose.
"I firmly believe that the unity is in the diversity and people being able to choose their own identity and choose one or two of those and to co-exist with one and other.
"It is also a win for the principles contained in the GFA which were the right set of principles and the right approach 20 years ago and still are now. It is a good underlining of the fact that that is a living breathing document."
Alliance MP Stephen Farry said it was a "huge victory" for the couple.
"Anyone from this part of the world understands that identity is incredibly complex," he said.
"There are people with mixed multiple identities but also people who are very clear that they have a sole identity and this is all about mutual respect and creating that framework so everyone is acknowledged in terms of who they are without other people putting labels on them."
Mr Farry said that someone else may take up the legal battle after June 2021, when the interim arrangements expire.
"We need to have a much wider conversation about how we can respect the GFA commitments in law right throughout these islands," he added.
A UK Government spokesperson said: "These changes deliver on the promise we made to the people of Northern Ireland in the ‘New Decade New Approach’ agreement earlier this year and demonstrate the UK Government’s continued and unwavering commitment to the Belfast (Good Friday) Agreement.”
The Home Office said the upper tribunal upheld the British Government's position that UK law is consistent with the GFA that the Home Office's policy on this has not changed. The Home pointed out that Mrs De Souza lost her court case and the court had ruled that her nationality derived from the jurisdiction she was born in under the law.
The Home Office said it would start accepting applications on 24 August and only those who are living in the country at the end of the Brexit transition period on 31 December this year would be eligible.