Jonathan Powell, who was Britain's chief negotiator during the Northern Ireland peace settlement, has urged governments to work more actively in talking and negotiating with terror groups, as he believes it is an essential part contributing to the peace process.
Speaking at an event with London-based think tank Chatham House, Mr Powell says his extensive and lengthy experiences dealing with Northern Irish republican leaders was key to eventually securing a peace agreement.
"What is required if you're going to make peace, is the ability to go onto the other side's turf."
He said negotiators "need to take some shared risks and be prepared to meet with them in those circumstances. It's about building trust."
The comments are seemingly an indictment of the official policies of many western governments who publicly refuse to negotiate with terrorists — something Mr Powell believes is ineffective when trying to negotiate peace.
"The first lesson is that we never say we're going to talk to terrorists, but we always do in the end," he said.
"Talking to terrorists is not the same as agreeing with terrorists. Agreeing is appeasement, talking is not necessarily."
The former Northern Ireland negotiator says that opening lines of communication with terrorist leaders from groups such as ISIL can be crucial in understanding more about their motives.
"Before we talk to them [terrorists] we say they are irrational, once we talk to them we understand a little bit more. They all have a rationality, you just have to find a way of understanding it."
Time to Talk to ISIL
While many governments in the Middle East and the West are trying to think of ways of ultimately defeat ISIL through military campaigns and the arming of rebel groups in Syria, Mr Powell says the West should start opening up lines of communication with Islamic State chiefs.
He believes that in the case of international terrorist groups such as ISIL and al-Qaeda, it is crucial to try and deal with the "root" of the problem, by talking to powerful leaders and chiefs of regional sub-branches.
"You have to deal with terrorism at the root. If you are trying to sort out the ISIL problem by talking to people in London or in Bradford who are trying to attack people then you wouldn't solve the problem. You need to go and address it at its root, which is this case is in the Middle East.
"In the case of ISIL, I do not for one moment suggest that we should be negotiating with ISIL now, as I distinguish between talking and negotiating. However history has shown that unless you spend start opening up these channels, you can spend a very long time fighting and get to a conclusion much later."
West Has 'Collective Amnesia' When Dealing With Conflict
With his experience is securing a peace agreement in Northern Ireland, Mr Powell believes the governments of the West, principally the US and UK, have continually failed in their efforts to secure peace agreements, particularly in the Middle East.
I don't know about negotiating with ISIL. They seem like the "you give an inch, they take a mile" type.— emokidsloveme (@emokidsloveme) January 28, 2015
While noting that it would be "ludicrous" to suggest there was a general model for dealing with terrorists and negotiating peace, Mr Powell says there are various "patterns" that have formed in modern terrorist conflicts.
"There are patterns as to what works and there are patterns as to what doesn't work."
However, he believes a failure to take note of these patterns, and learn from previous mistakes has severely hurt western negotiation efforts in recent decades.
"What we seem to suffer from is a sort of collective amnesia — we never remember what happened last time and we never remember the lessons we learnt from the time before, and as a result we nearly always start negotiating too late."
"You have to offer military pressure down, and then a political way out. Fighting and talking at the same time.
"You can solve a conflict as long as you have strong leadership, as long as you have the patience for the project, and if you can at least try and remember what happened last time and make some new mistakes instead of repeating the mistakes of others again and again."