The call was made in a letter, published by The Irish Times, signed by solicitor Michael Farrell, QUB law professor Dr Colin Harvey, and Liam Herrick of the Irish Council for Civil Liberties (ICCL).

They wrote: “In the drive to find common ground and momentum, we must guard against ignoring deeper issues at stake or undermining the foundations of the Belfast Agreement.

“The agreement was about more than just bilateral trade-offs between two states. It was about more than ending conflict. It was fundamentally about building a society based on the principles of human rights, equality and dignity.”

They warned that UK government plans to withdraw from the EU Charter of Fundamental Rights and scrap the Human Rights Act is “jeopardising the future that we have all been working towards”.

The letter ends with a call for “assurances that all who live in Northern Ireland will retain the protection of those human rights treaties currently in force”, including “the right to hold both British citizenship and Irish and EU citizenship without any difference in treatment”.

They also call for “assurances that the rights of non-EU citizens living in Northern Ireland will not suffer a diminution”.