The head of the Royal Black Institution says Northern Ireland's British culture is under attack and has launched an appeal to members worldwide.
Sovereign Grand Master Millar Farr wants support for his members' efforts to resist what he says is an on-going "attack" on their identity.
Mr Farr referred to the decision by Belfast City Council late last year to limit the flying of the Union Jack above Belfast City Hall as an example of attempts to deny their cultural rights.
He was speaking at a parade in Ballyronan in Co Derry on a day when around 18,000 were estimated to have taken part in Royal Black parades across the north.
Mr Farr appealed to institution members in Australia, New Zealand, the US, Canada, Togo and Ghana as well as England, Scotland, and the Republic of Ireland to back their campaign.
The decision to restrict the flying of the Union Jack to fewer designated days in line with public buildings elsewhere in the UK sparked protests and rioting by loyalists.
"The removal of the Union Flag from the City Hall in Belfast and other locations is regarded as an attack on our identity and culture," said Mr Farr.
"All our members, irrespective of where they reside, are law- abiding citizens of that particular country," he said.
"Those of us who reside in the United Kingdom regard ourselves as British and are proud to do so.
"We as loyal subjects of Her Majesty cherish the many freedoms which our democracy provides for us. One of these freedoms is the right to identify with the flag of the Nation to which we profess our allegiance.
"The flag of any country should be treated with dignity and respect and its appearance in public should not be limited or restricted. The adoption of such a policy is viewed by many as an attempt to dilute our identity and deny us the right to show allegiance to this United Kingdom to which we belong.
"Today we publicly state we are British and will do everything possible, in a lawful manner, to ensure we continue to live a peaceful and prosperous life under the Union Flag," he said, urging all members everywhere "to support us in our stand."