Three candidates from police services in Belfast, London and Dublin will compete for what is still one of the most prestigious posts in the UK.And foremost in their inbox will be the old problems which ended up dominating the tenure of outgoing chief Matt Baggott, those of the past, flags and parades.Former Assistant Chief Constable Peter Sheridan, now chief executive of Co-operation Ireland, helped put in place the structures and accountability measures of the PSNI.He has watched those structures change and evolve over time, but also how, in some places, society has stood still.He said: "We did all of those changes in policing."There was a new policing dispensation, a Policing Board, District Policing Partnerships, an Ombudsman's Office - all of that architecture went into place, including work within the organisation."But when you put those new officers out onto the streets, the policing environment hasn't changed to that extent and in many ways has got worse from the perspective of segregation."Society hasn't moved on and in many ways has got worse from the perspective of segregation.Peter SheridanIn the past weeks dealing with the past has come to the fore, none more significantly than over the arrest and four-day detention of Sinn Féin leader Gerry Adams.He was questioned over the 1972 abduction and murder of Belfast widow of 10 Jean McConville.He was released pending a report to the Public Prosecution Service.Mr Sheridan highlighted the inconsistencies of political support for the PSNI - how it ebbs and flows."You see it time and time again in that pick and mix support for policing," he continued."The whole past is acting like a bungee rope on policing."When incidents of the past are brought up, in the public's eye, it is almost as if it collapses time and today's officers are seen as being a part of it."There has not been the opportunity for mindsets to move on in the policing environment, while the actual police service has."He continued: "We need a way forward that deals with the issue of victims and survivors but also deals with the past in terms of a peace process that allows this community to move on."Dealing with the past, parading and flags has been attempted, most recently in the Haass, O'Sullivan process which ended in failure at the new year, with their efforts stuck in a political deadlock.Police officers have essentially become referees on the street to address our political failures.Jonny ByrneAcademics are keeping a close eye on developments and the constant tug-of-war between the past and the present.Jonny Byrne, from the University of Ulster, said: "Unfortunately public order policing has dominated the narrative in terms of the media."Obviously the media will pick up on the stories around protests and around flags and that is often when we see the images of batons and shields, which sometimes come to define how we view policing."And the softer side doesn't get reported all the time and it does exist across a number of communities and places."It is not just the old street disputes that continue to slow down the march toward new and normal policing, but the constant reminders of the past.Dr Louise Mallinder, from the Transitional Justice Institute, added: "I go to a lot of post-conflict societies and Northern Ireland seems to be unique in that the past is continually front page news."In Chile, which is still dominated by the Pinochet regime, people still live under his legal framework and it still dominates many aspects of public life and the electoral process for example to the point that people say it is not yet a meaningful democracy."But despite that context it is not on the front page and people are trying to focus on contemporary issues and so it surprises me the extent to which the past is so present in our lives here."The demands of the past are not going away. They need to be addressed.Dr Louise MallinderCurrent PSNI Assistant Chief Constable George Hamilton is seen by many as a front-runner for the top job.He faces stiff competition from Cressida Dick an Assistant Commissioner with the Metropolitan Police and Derek Byrne an Assistant Commissioner with An Garda Síochána.Whoever emerges as winner at the end of the interview process on 29 May will face not just the challenges of the here and now, but also the shadow of the past.Former chief constable Sir Hugh Orde recently described an absence of political will - dithering and stalling - on a process that finally addresses the issues of an unfinished peace.Dr Mallinder added: "Dealing with the past is something that has been evolving around the world over the past few decades."It's hard to say empirically with strong evidence about what works and what doesn't for many societies."These demands from the past aren't going to go away. They need to be addressed."Dr Byrne added: "The reality is no matter where you exist in the world good policing needs good politics and that's something we haven't really had."