The fact that cross-border co-operation is included in a new UK and Irish deal on the legacy of the Troubles is “a big step forward,” the tánaiste (Irish deputy PM) has said.

Simon Harris acknowledged that “trust is pretty shattered” on all sides of the issue, but he hoped the new framework would “win the confidence” of victims over time.

The new framework – which has received a mixed reaction – was unveiled on Friday by Harris and Northern Ireland Secretary of State Hilary Benn.

The deal seeks to heal a rift between London and Dublin created by the current Northern Ireland Troubles (Legacy and Reconciliation) Act.

Benn said the previous UK government’s “flawed, undeliverable and widely opposed Legacy Act” had caused “great pain and anguish to many people”.

The Legacy Act had included a conditional amnesty and was strongly opposed by many victims groups and all political parties in Northern Ireland.

Labour pledged to repeal the act and replace it after winning the last election, including agreeing a way forward with Dublin.

“As secretary of state I have been determined to help those families, who lost loved ones in the Troubles, including relatives of the families of British service people who did not come home, to find the answers they have long been seeking,” Benn said on Friday.

Speaking to BBC News NI, Harris said the inter-governmental deal was an “honest attempt” at providing reconciliation and justice for victims and survivors.

“My hopes are that for once and for all we can have an infrastructure that can try to move forward probably the most difficult, painful and complex issue outstanding in terms of our peace process on this island.”

During a joint press conference in Hillsborough Castle, County Down, Harris said it was an opportunity to end the cycle of “trauma and pain for another generation”.

“I believe, in my heart of hearts, that this is our best, and last, opportunity,” he said.

“We have to grasp it. It would be very wrong not to do so.”

He also described the framework as a moment of “imperfect opportunity”.

In a later BBC interview he explained: “I think everything is imperfect when it comes to legacy, when it comes to the deep scars and deep wounds that exist here on our island.

“We have peace but it can be a very frosty peace and I know – and I’ve certainly learned even more in the last nine months – the level of pain that people feel.”

The UK government said the deal involves a package of protections for veterans, including “a protection in old age”.

The Legacy Commission, born out the Independent Commission for Reconciliation and Information Recovery (ICRIR), will have independent oversight.

The new commission will also be “under a statutory duty not to duplicate the work of any previous investigations unless there are compelling reasons to do so”.

It will have two new directors for investigations.

The commission must also “take into account the health and wellbeing of potential witnesses at all times”.

Inquests which had commenced but had not ended before the current Legacy Act came into force last year will be restored.

Others which had not begun will be reviewed to identify a way forward.

It is understood changes to the ICRIR will also cover its commissioner for investigations role, a position held by former senior police officer Peter Sheridan.

Investigations by the commission will explore and exhaust all investigative leads.

Independent judges will preside over the commission’s inquisitorial public hearings, with families legally represented.

A cross-border Independent Commission on Information Retrieval will be set-up, initially for two years.

It will receive information on Troubles cases from individuals which cannot be used in prosecutions.

London and Dublin believe the two bodies reflect what was agreed, but never implemented, under the Stormont House Agreement in 2014.

In the Republic of Ireland, a dedicated legacy unit within the gardaí (Irish police) will be established and be operational by the end of this year, for co-operation on Troubles-related cases.

Ireland will bring forward legislation, where required, to facilitate full cooperation with the Legacy Commission, once its reform is enacted in UK law.

There will also be a ring-fenced €25m (£21m) fund to support victim participation in legacy processes in Northern Ireland.

Benn told the press conference the framework was “the best way forward to finally make progress on the unfinished business of the Good Friday Agreement”.

He added that he hoped those affected will see “this as a way forward in which they can have confidence, and will therefore give this plan a fair chance”.

Benn said that following the agreement of the framework, both governments will bring forward “human rights compliant” legislation which will include legacy commission reform.

He thanked the Irish and UK teams for the “constructive and collegiate spirit” in approaching discussions on legacy.

“We have now both an opportunity to try and deal with this and not put off difficult decisions for yet another generation.”

Harris said the process had been “a journey” and he sat with victims, survivors and families over the past year and was “moved by their dignity, courage and tenacity”.

He added that there was “no definitive solution” that would meet “all the demands and needs of every individual affected”.

However, he said they were announcing “a comprehensive set of measures” to “provide the maximum truth, justice and accountability to those who urgently need and deserve it”.

The BBC asked Harris about a separate document, published by the Northern Ireland Office (NIO) which outlined six protections for UK military veterans.

“I had an awareness that the British government would be outlining how they intended to interact with their veteran community,” he replied.

“Any accommodations afforded to any one group will be afforded to everybody in the legacy commission.

“So practical things like whether people can give remote evidence for example – they are structures that will apply to anybody engaging with the commission.”

Harris added the NIO document details were “not in the framework” and it was up to both governments to implement their agreement faithfully into legislation.

An ICRIR spokesperson said it was “led by the law and ready for reform”.

The framework provided “clarity” and was “important, timely and welcome”.

“Well over 200 people from all sections of society have already come to the commission leading to over 90 live investigations connected with over 170 deaths,” they said.

“Those dedicated investigations continue to grow daily. There will be no pause in this vital work.”