The comedian Harry Enfield created a character called "William Ulsterman". This caricature was quick to offend and to take offence, a little loud but above all, plain-spoken. Richard Haass, the latest international diplomat to come among us will quickly realise that if he is to succeed, he will have to persuade our political leaders that some very plain speaking is required of them. What is more, they are going to have to address not their traditional enemies, but their own respective constituencies.

The Haass negotiations are addressing the interrelated issues of flags, marching and dealing with the past. They may represent our last chance of an overarching settlement of the “unfinished business” of the peace process. Each of these issues speak to conflicting versions of history, identity and “rights”. Little wonder they are so emotive.

The past can appear overwhelming. The recent anniversaries of the Shankill Bombing and the Greysteel massacre showed us pain undimmed after 20 years. Sometimes the shrillest voices drown out reflective consideration as to what is legally, politically or socially feasible. The disastrous launch of the Eames Bradley report in 2009 was viewed by some as proof that it was all just too difficult.

Diversity of views
Such pessimism is overstated. With colleagues, I have spent the last year examining the relationship between truth recovery, amnesties and prosecutions. We have met victims, ex-prisoners, former security force personnel, political parties and members of civil society as well as the key criminal justice agencies to discuss the international, legal and historical components of these debates. Of course, there are diverse views. However, two are widely shared.

First, the current “piecemeal” approach – made up of inquests, public inquiries, the Police Ombudsman’s Office, the Historical Inquiries Team , and the work of human rights groups and journalists – isn’t delivering. Second, there is an appetite for jargon-free information so that people can make up their own minds.

Amnesties are part of the discussion because, simply, there is little chance of truth recovery without them. Amnesties can be perfectly lawful under international law and remain highly prevalent. Between January 1979 and December 2010, an average of 12 amnesty laws were enacted each year around the world. Blanket amnesties (such as those given by Gen Pinochet in Chile) are no longer legally viable. However, conditional amnesties linked to other processes, such as truth recovery, can be lawful.

The key legal obligations for the UK government are under the European Convention of Human Rights. In particular, article two creates a duty on states to conduct a full, effective, prompt and open investigation. Crucially, there is no requirement an investigation should lead to a prosecution, if it is linked to another objective, such as truth recovery.

History of amnesty
What those who denounce them as morally unacceptable need to recognise is that amnesties have already been widely used here. For example, in 1969, the Stormont government introduced an amnesty in the wake of the public order disturbances which applied to both civilians and RUC personnel. One beneficiary was Ian Paisley. More recently, the "disappeared" legislation introduced both North and South included an amnesty which prevented information gleaned from that process being used for prosecutions. To date, 10 bodies have been recovered. In the Saville Inquiry and others (including the Smithwick Tribunal), those who gave evidence could not be prosecuted on their own testimony. One beneficiary of this was Martin McGuinness.

Prosecutions remain notoriously difficult for historical cases and there is, bluntly, no prospect that scores will be successful. To date the Historical Inquiries Team has reviewed over 2,200 cases and only two successful conflict-related prosecutions have been achieved. Eyewitness accounts are unreliable; witnesses or suspects may be dead; forensic evidence may not exist or be contaminated – the IRA blew up the forensic lab as well as many police stations which held exhibits; the involvement of agents may collapse a trial and defendants will often remain silent. Even where prosecutions of a paramilitary suspect are successful, under the terms of the Belfast Agreement for pre-1998 offences, they will serve a maximum of two years.

A sensitive, respectful but honest appraisal of what is doable is required. Those whose loved ones were killed deserve the truth, and those who will write the history of the conflict need to know what truly happened.

Kieran McEvoy is professor of law and transitional justice at Queens University Belfast. He is director of the Amnesties, Prosecution and the Public Interest project, a partnership between Queens, the University of Ulster and Healing Through Remembering