In pictures: Twelfth of July Orange Order parades begin peacefully

Some 18 demonstrations are being staged to commemorate the 325th anniversary of King William III’s victory over James II at the Battle of the Boyne in 1690.

Police, government ministers, clergy and community workers said they hoped calm would prevail throughout the day and a flashpoint march in North Belfast passed off without incident.

Police Service of Northern Ireland (PSNI) assistant chief constable Stephen Martin said: “There is not that same level of tension.

“Yes, there is still annoyance with Parades Commission determinations and there is still a level of tension, but it has improved on last year.”

The acrid smell of smoke from bonfires lit on Monday night by celebrating loyalists still hung in the air in North Belfast and the roofing of a number of terraced houses close to one of the hulking blazes had been destroyed by fire.

Men in smart dark suits donned their orange collarettes or tied union flags on cars, some even using red white and blue hub caps for the day. Bottles of water were given out to discourage alcohol abuse.

Bands with polished flutes and massive Lambeg drums assembled on street corners, shoes shining and dressed in bright colours for the pageantry which awaited.

The biggest demonstration will be in Belfast with two “flagship” events in Kilkeel, Co Down and Portadown, Co Armagh.

The Independent Loyal Orange Institution will also hold a separate parade in Portglenone, Co Antrim.

While the vast majority of the 600 parades are free of trouble each year, the threat of disorder at a small number of marching flashpoints always has the potential to mar the day.

More than 3,000 police officers are on duty, and there are contingency plans in place to call on support from other UK forces if required.

Undoubtedly the largest and costliest security operation will be rolled out in Ardoyne - a volatile community interface in North Belfast where attempts to end the bitter dispute over a contentious parade have failed. Air support, specialist firearms teams and baton rounds will be available if needed.

This morning, nationalist protesters chanted and held slogans proclaiming the Orangemen not welcome.

A long line of police, riot trained but without batons or shields, separated the two.

A drummer in the flute band hit the instrument enthusiastically just yards away. Orangemen in their Twelfth finery looked at the residents without speaking. Some were close enough to shake each other’s hands.

Last year, spontaneous rioting broke out when loyalists clashed with police who had blocked access to the contested stretch of the Crumlin Road.

This year, talks between loyalists and nationalists about the contested march ended without agreement a short time before the demonstration.

Police Federation chairman Mark Lindsay said morale among rank and file officers at this stage was good.

He said: “There is an acceptance that this is a fairly well rehearsed event.

“Everybody, from the officers on the ground to the community, wants it to go off peacefully.”