The UK would be following Vladimir Putin’s lead it if took the “absolutely outrageous” step of withdrawing from the European Convention on Human Rights, an Irish parliamentary committee has heard.

Such a move would undermine the human rights protections that are central to Northern Ireland’s landmark Good Friday peace agreement, Amnesty International warned.

Amnesty’s Northern Ireland programme director, Patrick Corrigan, was giving evidence to an Oireachtas committee tasked with assessing the implementation of the 1998 peace accord. MPs from Northern Ireland sit alongside Irish TDs and senators on the committee.

Mr Corrigan was providing his analysis of the UK Government’s Illegal Migration Act and its potential consequences for the Good Friday deal.

The hearing came a day after the UK Supreme Court ruled that the Government’s flagship Rwanda asylum policy was unlawful.

The UK’s highest court rejected the Government’s appeal over its policy of removing asylum seekers to Rwanda if they arrive by unauthorised means.

The ruling has prompted renewed calls from the right of the Conservative Party for the Government to withdraw from the ECHR to remove one of the main legal obstacles facing the Rwanda policy.

Russia left the Convention in 2022 as a consequence of its expulsion from the Council of Europe.

Human rights protections guaranteed within the Good Friday Agreement are based on the ECHR framework.

Mr Corrigan said the Irish Government needs to be vigilant to the potential consequences of what he described as a UK move to step away from its international human rights obligations.

“While the UK Government may not withdraw from the European Convention… and that obviously would be an absolutely outrageous step to take, sort of following Putin’s Russia in withdrawing from the European Convention, but nothing can be ruled out given some of the noises that we hear at least on the (Conservative) back benches – they used to be on the front benches as well, maybe it’s on the back benches now – around withdrawing from the European Convention,” he said.

“And that’s still a threat that hangs over all of the debate around this.

“Obviously, there is an Irish interest there in protecting the Good Friday Agreement in all its parts, including the chapter on human rights and equality safeguards for people on the island.”

Mr Corrigan also expressed concern about the potential fate of non-Irish citizens living in the Republic of Ireland who, while not having a visa to be in the UK, travel north of the border, potentially just to do some shopping.

He said that, under the Illegal Migration Act, they could find themselves being detained and sent back to their home country of origin or a third country, with limited legal avenues to challenge it.

“There is a de facto hardening of the border for people moving from one side of the border to the other,” he said.

“And while there are protections in place for people who have UK or Irish citizenship, who hold those passports, for people who do not there are new realities that they have to face.”

He added: “The consequences now are extraordinarily severe; say, being removed to a third country or removed to a country from which you had fled and that there are risks to your rights – to safety, right to life.

“And, crucially, one of the rights that is removed is the right to adequately challenge the decisions that are made about you and your removal and your detention first of all, and then your removal, that that legal challenge to which one is entitled under the European Convention and also entitled under EU law has now been swept aside by the Illegal Migration Act.

“So not only can you find yourself caught up in this sort of Kafkaesque situation of being detained and facing deportation, that your opportunity to challenge that has also effectively been removed or massively diminished, so that you enter into this netherworld of UK immigration policy and there’s very little way out of it again.”