At the end of July, the Republican Club announced that the Derry Citizens’ Defence Association (DCDA) had been established to replace the DCAC. Its purpose was to “defend the area.” Most groups active in the Bogside acquiesced. 

Preparations began to repel any incursion on 12 August, when an annual Apprentice Boys’ procession through the city commemorated the siege of 1688. Petrol bombs, stones and barricade materials were stored close to the entrances to the area. 

A second police/loyalist attack on Unity Flats, Belfast, on 2 August intensified Derry apprehension. 

The Apprentice Boys’ procession was seen by Derry unionists as marking a resolute stand by their forebears against despotism and the divine right of kings. It was experienced just as plausibly by Bogsiders as an annual reminder of their lesser status in their own town. Recent events had helped dispel acceptance of that status. Barricades were erected late at night on 11 August, in anticipation.

DCDA chairman Sean Keenan told a rally in the GAA’s Celtic Park:

“If we have to fight, then let us for God’s sake fight as peace-loving people.”

British troops were put on standby to intervene if the police proved unable to maintain order on the Twelfth.