Political leaders and police chiefs from both sides of the Irish border will be among mourners at the funeral of a Roman Catholic officer murdered by dissident republicans.
Stormont First Minister Peter Robinson and Deputy First Minister Martin McGuinness will be joined by Republic of Ireland premier Enda Kenny at a requiem for Pc Ronan Kerr.
Matt Baggott, chief constable of the Police Service of Northern Ireland, and his southern counterpart Garda Commissioner Martin Callinan will also pay their respects at what is expected to be a huge funeral in the small Tyrone village of Beragh.
As the service takes place on Wednesday afternoon, large crowds are expected to gather 70 miles away in Belfast city centre at a trade union-organised peace rally to protest at the weekend killing.
Pc Kerr, 25, died in Omagh on Saturday when a booby trap bomb detonated under his car.
Intent on thwarting progress toward making the police more representative of both main traditions in Northern Ireland, dissidents have actively targeted Catholic officers.
But Pc Kerr's heartbroken mother Nuala Kerr has appealed to fellow Catholics to stand up and be counted and not be put off joining the PSNI.
Independent charity Crimestoppers has offered a £50,000 reward for information that will help detectives catch the constable's killers.
The presence of Mr Robinson and Mr McGuinness at the service is highly symbolic, for different reasons. For the Democratic Unionist leader it will be the first Catholic church service he has attended, while the presence of the Sinn Fein veteran at the funeral of a serving member of the security forces would have been unimaginable before mainstream republicanism made the historic decision to back the PSNI four years ago.
After announcing his decision to attend the funeral on Tuesday, Mr Robinson told a meeting of business leaders in Belfast that the murder served only to strengthen the resolution of politicians to make peace work.
