He was awarded the 2016 Nobel Peace Prize for, the committee said, his “resolute efforts to bring the country’s more than 50-year-long civil war to an end, a war that has cost the lives of at least 220,000 Colombians and displaced close to six million people”.

Santos oversaw the 2016 peace agreement between the Revolutionary Armed Forces of Colombia (FARC) and the government, concluding the armed conflict.

Al Jazeera interviewed Santos at the One Young World 2023 summit last month in Belfast, to speak about the lessons learned in Colombia from Northern Ireland’s peace process and where transitional justice efforts stand respectively in the two territories.

Al Jazeera: What significance does the Northern Ireland peace process have for the conflict resolution efforts you have spearheaded in Colombia?

Juan Manuel Santos: The peace process here was in a way an inspiration for us. It was a conflict that had lasted for so many years and finally ended.

I copied other aspects of the Northern Ireland peace agreement – for example, the back-channelling and the confidentiality at the beginning. With the help of international advisers who were not engaged in the day-to-day of Colombian politics, I said, “This is what we must do.” And that blueprint was extremely, extremely useful.

But we also learned what not to do. For example, the Northern Ireland peace agreement did not give importance to implementation. And I think we learned that we should – that’s why we included implementation as a specific point in the Colombian peace process.

Another thing that was not done here, which we did do in Colombia, was putting victims at the centre of negotiations. If you do this – their rights to justice, their rights to the truth, their rights to justice and non-repetition – that helps tremendously the process of healing the wounds of war that has been going on for so long.

Today, you see generals of the Colombian military facing victims and admitting that they committed war crimes and crimes against humanity – that they killed their sons, without any reason. And to see that! People thought that would never happen, but it is happening right now.

Part of the tensions that are still present here in Northern Ireland, 25 years after, is because you did not do what we did in Colombia. We’re going through this very difficult process at the moment of trying to heal the wounds created by so many years of war. It’s not an easy task, but it’s a necessary one if you want a sustainable peace in the long run.

Al Jazeera: This has been brought into sharp focus here by the British government’s new Northern Ireland Troubles (Legacy and Reconciliation) Bill. How have you viewed developments around it?

Santos: That’s one of the consequences of not having a transitional justice system like the one we have in Colombia. We built that in order precisely to avoid the problems you are having here, 25 years later, with the British government.

It has been trying to pass a law that will give [an effective] amnesty to the people responsible for war crimes – for many people this is, of course, unacceptable. If you had had a transitional justice [structure or framework ], these types of problems would not appear 25 years later.

The Colombian peace process is the only peace process in the world where the two [warring] parties agreed to create a special tribunal and to submit to it. Usually, it is a tribunal that is imposed from the outside – by the United Nations, or whatever [body] – but never had two parties created their own process [transitional justice mechanism] and submitted to it in this way.

The international community is less and less prone to accepting amnesties for war criminals and crimes against humanity – this can appear to make peace deals harder to apply, but it makes sense when you come to try and heal the wounds, a fundamental part of any peace process.

Al Jazeera: Where is the Colombian peace process poised now? 

Santos: Unfortunately, my successor [Ivan Duque Marquez] – who was against the peace process – dragged his feet in the implementation of the peace process. This was very damaging and had there been an earlier implementation with the FARC, the much-needed process of healing our society’s wounds would have got under way much faster.

The president of this new government [Gustavo Petro] has promised that he will implement the peace process, and I hope he does. Because his idea of building what he calls “total peace” has to be done using the peace process that was signed with the FARC as a necessary condition. Without doing that, his efforts will fail.

So what I hope – and what I’m asking for – is to accelerate the implementation of the peace process that was signed several years ago. Because that would give him the legitimacy and the credibility to build on that process.

If he thinks he can build a new peace process without implementing what has already been [agreed and] signed, then he will fail.

The Colombian peace process was probably the most ambitious peace process ever signed, and it’s been described [externally] in those terms. We did not only address the DDR – demobilisation, disarmament and reintegration – but we also addressed the causes of the conflict. We went much further to negotiate, for example, agrarian reform that this government is trying to put in place and that the last government put on hold. We went much further to try to find a solution to the drug-trafficking problem – which the last government also put on hold and we’re still suffering the consequences of that. We even had an ethnic chapter, a gender chapter – which has not been implemented fully yet.

If you do all of that, it is a marvellous programme for any government. So, if the Petro administration simply does [all of] that, he will be considered a good president when they finish. But if he, in a way, concentrates on his [idea of] “total peace” at the expense of what has been [agreed and] signed [already], then he will be in trouble.

This interview was lightly edited for brevity and clarity.