The British government cannot just "throw the Good Friday Agreement under the bus" to pursue a shortsighted Brexit agenda, a campaigner has said.
Rallies held in both London and Belfast on Saturday, dubbed #WeAreIrishtoo, called on all governments to uphold the Good Friday Agreement in all its parts.
The protests came after the UK Government rejected Emma DeSouza's American husband's application for a visa over her refusal to call herself British.
Mark Hughes, who was born in Newry and now lives in Lewisham, south London, said Ms DeSouza's case highlights the "legal grey area" that Northern Irish citizens could fall into.
"The Good Friday Agreement gave us peace, normality and a shared future no matter what - we could be British, we could be Irish and we could be both," the 33-year-old said.
Speaking outside the Northern Ireland Office in Westminster, the paralegal said the murder of journalist Lyra McKee has shown "just how fragile" peace is.
"The current stance of the Tory government dumps on that parity of esteem which is provided by the Good Friday Agreement."
He added that they do not want a "two-tiered society where EU rights are given to one group and not the other".
Under the terms of the Good Friday peace agreement of 1998, people from Northern Ireland have the right to hold UK or Irish citizenship, or both.
Solidarity with Northern Irish peopleApril 20, 2019
But Ms DeSouza and her husband Jake were told after their wedding in 2015 that his application for a family member residence card to remain in Northern Ireland had been rejected because she applied for the visa as an Irish national.
She and others have claimed they were being forced to declare as British, or formally renounce British citizenship they insist they never held, to engage with the residency application process.
In a video posted on Twitter ahead of the rally in Belfast, which she attended, Ms DeSouza said in the current climate it is important to come forward and stand up for the Good Friday Agreement, peace process and their rights which are "under threat".
Ms DeSouza has previously said the "lack of legislative protections" for citizens in Northern Ireland is because the Good Friday Agreement "has not been fully implemented".
This legislative gap which leaves citizens vulnerable will "only widen after Brexit", she has said.
With a silence held in memory of Ms McKee, Mr Hughes said they want the Government to recognise the "special circumstances" of Northern Ireland citizens.
Derry Girls actress Siobhan McSweeney attended the rally in London and said that as someone from the Republic of Ireland, she felt a "responsibility to support Northern Irish voices".
"What I see is a sleight of hand by the British Government to dismantle the Good Friday Agreement which was hard-won and hard-fought for, and a deeply-treasured agreement that allows citizens of Northern Ireland to identify as Irish as British or as both," she told the Press Association.
Mr Hughes warned how the current leadership vacuum in Northern Ireland "has allowed dissidents to rear their ugly heads" and how no-one wants to go back to borders and violence.
"If anything this protest and the spirit of it - given what has happened - is to show that the Good Friday Agreement has done so much, so please don't tear it up," he added.
PA & Digital Desk