The main policing stories of 2011
Ronan Kerr's funeral was a stark reminder of the past, as well as a sign of how much has changed in recent years.
The sight of GAA members in club colours handing over his coffin to uniformed members of the PSNI would have been unthinkable just a short time ago.
The funeral produced highly symbolic images of political unity.
DUP leader and First Minister Peter Robinson attended a Catholic church service for the first time, and Ulster Unionist leader Tom Elliot faced an unsuccessful attempt to expel him from the Orange Orange as a punishment for his attendance.
But it was the sight of GAA members and PSNI officers standing shoulder to shoulder, united in grief, that best demonstrated how much the political landscape has changed.
Ronan Kerr symbolised the new face of policing. A young nationalist, he was exactly the kind of recruit the PSNI was eager to attract.
In the eyes of his killers, he was also the kind of officer they were eager to attack in an attempt to dissuade young Catholics from joining the police.
But there is no evidence that large numbers of Catholic police officers were intimidated into leaving the PSNI.
However, in spite of the public outcry that followed Ronan Kerr's murder, dissident republicans continue to target police officers.
Within days of the killing, a well-placed security source said there had been "no lessening of the dissident's operational tempo and no diminution of activity".
Combating dissident activity
The operational tempo of the police increased during the year to counter the threat, as did the resources available to the PSNI.
Chief Constable Matt Baggott secured additional funding of almost a quarter of a billion pounds specifically to combat dissident activity during the next four years.
There are no details of how precisely the additional money is being spent, but it is understood that a large proportion has been allocated to intelligence gathering, including human and electronic surveillance of suspects.
The police say it has paid dividends.
During the 11 months up to the end of November this year, the PSNI conducted 388 searches, made 164 arrests and charged or reported 80 people in relation to dissident activity.
Dissident groups have carried out a series of attacks and a number of others have been foiled.
They continue to pose a serious threat, with police officers their primary targets.
However, they were unable to disrupt a number of high profile events during the past year.
The assembly elections, the Queen's visit and the MTV awards were all viewed by the police as high value targets that dissident groups would strive to disrupt, but they passed off without incident.
Security sources caution against complacency and say the dissident groups still retain the capacity and technical knowledge to cause death and destruction.
The PSNI is planning to improve its technical capability to deal with the threat.
The BBC revealed in November that the police were examining the possibility of deploying small unmanned aerial vehicles, often referred to as drones, in the skies above Northern Ireland.
These could be used as part of the police response to major incidents, as well as the surveillance of specific areas and individuals, at a fraction of the cost of deploying a helicopter.
Discussions have already taken place with the Civil Aviation Authority, which must grant permission for the use of the mini aircraft.
But while the PSNI is looking to the future, the past continues to cast a shadow and threatens the political consensus around policing.
The rehiring of former RUC officers who retired early with generous redundancy packages has become an issue of heated debate.
The police and unionists say the experience and knowledge of the retired officers is vital, while Sinn Fein and the SDLP view the practice as undermining the Patten reforms of policing.
Sinn Fein has asked the government's spending watchdog, the Northern Ireland Audit Office, to investigate.
Matt Baggott spoke during the past year about his desire to see policing here de-politicised.
As 2011 draws to a close, that appears highly unlikely.