The Northern Ireland Troubles (Legacy and Reconciliation) Act 2023, which the Irish government is challenging in a rare interstate application to the European Court of Human Rights, will end most legal proceedings linked to legacy cases.

A new Independent Commission for Reconciliation and Information Recovery (ICRIR), headed by former lord chief justice Sir Declan Morgan, will instead carry out what the UK government insists will be more “robust and effective” investigations into Troubles-related cases.

ICRIR, which has been operationally established from today, was originally intended to have the controversial power to offer immunity in some circumstances to those who co-operate with it, though this part of the Act was disapplied following a ruling by the High Court in February.

Speaking today, Northern Ireland secretary Chris Heaton-Harris said: “If the independent commission is given an opportunity to demonstrate its effectiveness, I am confident that it will deliver results.”

However, Gráinne Teggart, Northern Ireland deputy director at Amnesty International UK, said today’s milestone marked “a cliff-edge for truth, justice, and accountability for victims of the Northern Ireland conflict”.

“The Troubles Act 1st of May guillotine for judicial processes has acted as an incentive for the state to frustrate legal proceedings and continue to grossly fail victims,” she said.

“The UK government should be utterly ashamed of the suffering they have heaped on victims by this appalling Act. This law is a significant attack on rights, a disturbing interference in the justice system and a complete affront to justice. It also sets a dangerous international precedent and must not stand.”

Ms Teggart added: “We are determined this will not be the end — the Troubles Act must be repealed. Legal challenges to the Act continue and the upcoming general election will provide the next UK government with the opportunity to prioritise righting this historic wrong.

“We urgently need victim-centred processes established and an end to a culture of slashing away at basic rights.”

Update (2/5/24): A previous version of this article did not reflect that ICRIR does not now have the power to offer conditional immunity to those who co-operate with it.