Ulster Covenant: Thousands due at centenary parade
29 September 2012 Last updated at 08:59 BST
Northern Ireland's biggest policing operation in 20 years is due to get under way in Belfast later.
It is estimated as many as 30,000 marchers will take part in the parade to mark one of the most significant dates in unionist history.
The six-mile march from central Belfast to Stormont will mark the 100th anniversary of the Ulster Covenant, to oppose Home Rule for Ireland in 1912.
Mark Simpson reports.