Police fired plastic bullets and fought running battles with a mob of loyalists trying to break through their lines to march through a Republican area of Northern Ireland last night.
The situation, involving the worst loyalist violence in a decade which could pose a serious threat to the peace process, deteriorated when hundreds of Orangemen broke through police lines in their efforts to get on to the Garvaghy Road through a nationalist area of Portadown, Co Armagh.
As violence flared in Portadown, elsewhere in Northern Ireland protests in support of the Orangemen erupted. In the most serious, the County Antrim ferry port of Larne was virtually under siege with lorries blocking the main road serving the harbour.
As the protest became a tense stand-off early this morning, Orangemen warned that the trouble could recur today, the most significant day on the Orange order's calendar.
The Portadown mayhem, in which a number of police officers and marchers were injured, came just after Ian Paisley, the leader of the Democratic Unionists, made a rabble rousing speech to thousands of supporters. "We will die if necessary, rather than surrender," said Mr Paisley. "If we do not win here this battle is lost, so it's a matter of life or death. It's a matter of Ulster or the Irish Republic. It's a matter of freedom or slavery."
Within minutes of his speech ending and the violence beginning, Mr Paisley, David Trimble, the Ulster Unionist MP for Upper Bann, and a small delegation were pushed through police lines by the mob.
Looking shaken, Mr Paisley held a hurried discussion with senior police officers searching for a solution to calm the highly charged situation. But as he talked the mob continually out-flanked police who tried to keep them off the Garvaghy Road, the subject of an earlier police banning order.
Officers firing plastic bullets fought hand-to-hand battles with the mob as protesters tried to scale hedgerows and open gates. Police reinforcements were drafted in as the rioters got closer to the nationalist Churchill Park Estate where residents stood in the late-night drizzle fearful for their homes.
Police ranks, swelled by reinforcements, finally held the breakaway element of the crowd on the edge of the Catholic Ballyoran Park housing estate, just a couple of hundred yards from the Garvaghy Road.
A narrow twisting road in the Northern Ireland countryside was the backdrop to the latest test of the increasingly fraught peace process as swelling ranks of Orangemen had maintained their stand-off with police over their right to march along a specific route.
Nationalist community leaders portrayed the confrontation as a trial of strength between the authorities and the loyalists with the outcome having a direct bearing on the peace process.
But as leaders of the Orange Order held discussions with senior police in an effort to find a compromise that might allow some of their members to walk along the Garvaghy Road, leading loyalists accused the Government of appeasing republican opinion by preventing the march.
Patrick Mayhew, the Northern Ireland Secretary, said the decision was purely an operational one taken by the Royal Ulster Constabulary seeking to uphold the rule of law and refused to intervene in the dispute, confident that a solution would be found eventually.
Ministers last night angrily blamed Ulster Unionist leaders for inflaming loyalist protesters. They were highly critical of Mr Paisley and Mr Trimble for taking part in the protest.
Ministers accused Ulster Unionist politicians of risking igniting the powder keg.
"The bastards," said one ministerial source. "They are supposed to be showing leadership. We were just leaving it to the RUC. It's certainly not the fault of the police. Some of them have been on duty for 36 hours."
Sir Patrick is expected to call an emergency meeting of ministers today to discuss the worsening security situation in Northern Ireland.
Early this morning Mr Paisley and Mr Trimble and senior loyalist figures returned to the scene of the protest and declared that they had negotiated a solution which would allow a group of Portadown Orange lodge members to march along the route in the early hours. It was believed this would defuse the situation.Reuse content