It had been hoped that scenes of violent confrontation had disappeared from the streets of Northern Ireland.
But police in Belfast have come under attack for the second night in a row.
Petrol bombs, bricks and bottles were hurled at officers by Catholic youths at the climax of the annual Protestant marching season.
Water cannon were used to control the crowd.
Local priest Father Gary Donegan summed up the problem:“You have social deprivation, you have a lot of difficulties with young people, unemployment and just idle hands, idle minds and for young people, you know it’s an opportunity to come, excitement for the thrill of it.”
The yearly July the 12th marches celebrate the Protestant victory at the Battle of the Boyne – seen as a provocation by Catholics.
The peace process may have resolved Northern Ireland’s political issues, but it is clear that social problems remain.