The Orange Order and hundreds of marching bands will take part in more than 550 parades in 19 locations across Northern Ireland to mark the Twelfth of July.

The annual parades mark the Battle of the Boyne, when William of Orange – also known as King Billy – defeated King James II in 1690.

Parades must be lodged to the Parades Commission and approved in advance.

The commission has imposed restrictions on a contentious march on the night of 12 July in north Belfast close to the Ardoyne shopfronts.

Across Northern Ireland, about 4,000 police officers will be on duty, which is approximately two thirds of the force.

The cost of the policing operation for the Twelfth period last year was more than £4m.

Although there has been some tension around the parade route in north Belfast, the police said last month they did not detect “an appetite for disorder”.

An agreement, dating back to 2016, ended the dispute in the Ardoyne area but it collapsed three weeks ago.

Efforts have since been made to try to defuse the tension and avoid any confrontation.

The grand secretary of the Orange Order, Rev Mervyn Gibson, told BBC NI’s Good Morning Ulster radio programme he didn’t see “any appetite for violence, certainly not from our side and I don’t think from any sides”.

“We want a peaceful day and for everyone to enjoy it, so I wouldn’t see any difficulties today but it needs to be sorted out quickly after he Twelfth of July,” he added.

“This is a day when hundreds of thousands of people will be out to see the parades, tens of thousands of Orangemen and bands will parade right across Northern Ireland and people want to enjoy themselves.”

However, he added: “I have to be honest, I think relationships are probably the worst they’ve been in about 20 years.

“There are a whole lot of factors for that – political agitation around calls for a United Ireland and other things.”

The Orange Order says that around 600 marching bands will be involved in today’s parades.

The order’s grand master Edward Stevenson, said it will be an “impressive spectacle”.

Mr Stevenson said: “Across the 18 venues, we will have tens of thousands of men, women and young people taking part in an event which has been faithfully maintained for well over 200 years.

“Many thousands more will line the streets of host cities, towns and villages.

“There is simply no other event on these islands that can bring such vast numbers of people onto the streets as our processions, either by taking part or simply to watch them go by.”

The order’s Rev Gibson said the institution is in a “great position”.

“For the first time in many years our membership is increasing – our junior movement increased by 40% last year,” he said.

“We’re seeing more and more activities throughout the year – we’re not a one day a year organisation and there’s a massive growth in Orange activity around the country.”

The Twelfth is a bank holiday in Northern Ireland.

Banks and some businesses will be closed on Friday 12 July.

After a week of wet and rather chilly weather the forecast for Friday shows a distinct improvement.

A ridge of high pressure is set to build, so 12 July looks to start dry with sunny spells.

Cloud will build up later in the day but staying dry throughout.

Temperatures are up a little on what we’ve seen through the week, but still below average for mid-July with highs of 16-18 degrees.

The Police Service of Northern Ireland has released information on traffic closures and disruption expected on Friday and Saturday which can be found on its website.

In Belfast, the main Twelfth of July parade will start at 10:00 BST on Friday from the Orange Hall in Carlisle Circus and will move towards Belfast City Hall, where a wreath-laying ceremony will take place.

The parade will move along Donegall Square North, Donegall Square West, Bedford Street, Dublin Road, Shaftsbury Square, Bradbury Place, Lisburn Road, Balmoral Avenue and Malone Road.

At 15.30 BST, the main parade will start its return journey back to Carlisle Circus, where districts will branch off to their own areas.

In Londonderry, 57 Orange lodges from eight districts will make their way through the city centre accompanied by 36 bands before parading to the field in the Waterside.

Victor Wray, from City of Londonderry Grand Orange Lodge, said he expects about 3,000 people to take part.

The main parade will depart from Glendermott Road (end of Bonds Street) at 11:30 BST. It is expected the entire parade will have arrived in Wilton Park for 14:00 BST.

Translink has said bus and train services across Northern Ireland will be operating on holiday timetables on 12 and 13 July, with local rail and enterprise services operating on the current summer timetable.

Translink has warned that due to parades and road closures some stops will be missed on bus routes and advised passengers to check its website.

The locations for the 18 main demonstrations include Londonderry, Ballymena, Carrickfergus, Newtownards, Ballygawley and Moneymore.

The longest parade, a 12-mile return trip, is from north to south Belfast, via the city centre.

The largest gathering will in the village of Killylea in County Armagh.

Other Twelfth demonstrations taking place include:

• Ahoghill
• Ballymena
• Belfast
• Broughshane
• Cloughmills
• Carrickfergus
• Derriaghy

• Annalong
• Ballynahinch
• Gilford
• Newtownards

• Ballygawley
• Benburb
• Newtownstewart