Clip from archive compilation programme 'Understanding Northern Ireland'.

Features, Robert Porter (Minister of Home Affairs) speaking about the Burntollet Bridge march, where accounts of police brutality had been reported. This, Porter credits as a product of a smear campaign. He justifies bringing the army in as it's "necessary to take measures accordingly" and refutes the assumption that Northern Ireland is on the verge of civil war.  

It was a People's Democracy march from Belfast to Derry which was attacked whilst passing through Burntollet. The march had been called in defiance of an appeal by Northern Ireland Prime MinisterNorthern Ireland Prime MinisterTerence O'Neill for a temporary end to protest. 

At Burntollet an Ulster loyalist crowd numbering in the region of 300 - including 100 off-duty members of the Ulster Special Constabulary (USC) - attacked the civil rights marchers from adjacent high ground. Loyalists celebrated the attack as a victory over Catholic "rebels".

• NI Direct - PRONI