Northern Ireland's independent Parades Commission, seeking to avert street violence, on Monday barred Protestant marchers from passing next weekend through a Catholic part of the strongly pro-British town of Portadown.
The parade by the Orange Order, viewed by Northern Ireland's Catholic minority as a threatening expression of Protestant triumphalism, touched off rioting across the province in 1996 and 1997.This year's parade, one of an annual series around Northern Ireland, is due to take place Sunday.
The chairman of the commission, Alistair Graham, said it had not decided on the ban lightly.
But he told a news conference the threat to public order could not be overlooked in light of the failure to negotiate a compromise route that would have avoided the Catholic Garvaghy Road.
"Given the absence of any positive move towards accommodation, we cannot see at this stage how a parade could proceed again this year down the Garvaghy Road without having a serious adverse impact on community relationships both locally and more widely across Northern Ireland."
The Orange Order, an ancient Protestant brotherhood, regards the marching route down the Garvaghy Road as a traditional right that it is especially determined to uphold at a time of rapid political change in Northern Ireland, where elections have just been held for a power-sharing assembly.
Northern Irish Catholics, by contrast, regard the parade as a crude provocation by the Protestant majority.