orange order
Members of the Provincial Grand Black Chapter of Scotland march in Dumbarton, ScotlandGetty

Scotland's biggest ever Orange Parade is set to take place this weekend, as thousands of pro-unionists show support for the 'No' vote ahead of the country's referendum.

As many as 15,000 members of the Grand Orange Lodge of Scotland are expected to march through Edinburgh on 13 September as part of a rally to back the Better Together campaign.

The parade, which will pass through the capital's Royal Mile, will contain banners, bands and members in full outfits to show how they are "Proud to be British".

History of the Orange Order

The Orange Order, is a Protestant fraternal organisation founded in Northern Ireland in 1795 – during a period of Protestant-Catholic sectarian conflict – as a Masonic-style brotherhood sworn to defend Protestant supremacy.

Its name is a tribute to the Dutch-born Protestant king of England, William of Orange, who defeated the army of Catholic king James II at the Battle of the Boyne (1690). Its members are referred to as Orangemen.

Although strongest in Northern Ireland, the Order also has a significant presence in the Scottish Lowlands and lodges throughout the Commonwealth and United States.

Politically, the Orange Order is a conservative British unionist organisation with links to Ulster loyalism, and is campaigning against Scottish independence

The march arrives after the Alistair Darling-led Better Together campaign restored its lead in the polls after previously falling behind to Alex Salmond's 'Yes' campaign for the first time.

The Orange Order assured the parade will be in "good humour" and predicted there will not be the sort of disorder which has plagued similar walks in Scotland and Northern Ireland.

During an Orange Walk in Glasgow in July, a 12-year-old girl was left with blood pouring down her face after she was accidently struck with a glass bottle after a fight broke out nearby.

Following the injury to the girl, Labour MP Jim Murphy called for the upcoming Edinburgh march to be cancelled, adding the incident left a "scar on Glasgow".

He added: "I am disgusted. The march before the referendum vote shouldn't go ahead. Better Together want nothing to do with the Orange Order."

A Orange Order spokesperson said: "It's intended that the good humour will spill over into the parade which will see traditional lodge banners supplemented by referendum banners bearing the message: 'Proud to be Scottish – Proud to be British'. The parade will have a family atmosphere with the Order bringing its junior members, and it will be bedecked with Union flags, Saltires and balloons."

Police said they have all the necessary arrangements in place in order to deal with the parade.

A spokesperson added: "Police Scotland's priority is to ensure public safety and security and we will uphold the right of anyone to march and demonstrate peacefully.

"This event, like every other of this type, will be policed appropriately and proportionately and we will respond appropriately to any issues which arise, dealing accordingly with anyone who breaches the law."

Voters are to decide whether Scotland should be an independent country or not on 18 September.