When The Ulster Defence Regiment was formed in 1970 a decision needed to be made about the badge officers and men of the regiment would wear on their headdress. The officer who is alleged to have arrived at the solution took a Royal Ulster Rifles cap badge and broke off from the bottom of it the scroll bearing The Royal Ulster Rifles’ motto “Quis Separabit”. This left a simple harp and crown that was recoloured gold and worn by The Ulster Defence Regiment until merging with The Royal Irish Rangers in 1992.

Soldiers of the new Royal Irish Regiment continued to wear the gold coloured UDR cap badge in berets whilst officers wore an embroidered silk and wire cap badge on green backing cloth sewn onto the beret. Later, a new silver cap badge was issued to all ranks to be worn in the caubeen, the formal headdress worn by soldiers of all the antecedent regiments and by The Royal Irish Rangers. The beret has since been removed from the Regiment’s dress regulations and the Caubeen is now worn in all forms of dress in barracks. In 2007, the cap badge was reworked to give sharper definition and a finer finish, with a green enamel backing separating the harp strings.