Ulster Defence Regiment

The Ulster Defence Regiment (UDR) was an infantry regiment of the British Army. It became operational in 1970, formed on similar lines to other British reserve forces but with the operational role of defence of life or property in Northern Ireland against armed attack or sabotage. The UDR replaced the Ulster Special Constabulary ("B-Specials") along with a separate police reserve, to assist the regular Armed Forces. It was the largest infantry regiment in the British Army, formed with seven battalions and an extra four added within two years.

The regiment consisted overwhelmingly of part-time volunteers until 1976 when a full-time cadre was added. Recruiting from the local community at a time of intercommunal strife, it was accused of sectarian attitudes and collusion with loyalist paramilitary organisations through most of its term. The regiment was intended to be nonpartisan, and it began with Catholic recruits accounting for 18% of membership, however due to various circumstances by the end of 1972 the Catholic membership made up around 3% of the regiment's soldiers.

In 1992, the regiment was amalgamated with the Royal Irish Rangers to form the Royal Irish Regiment. In 2006, the Royal Irish Regiment was awarded the Conspicuous Gallantry Cross, which entitled the UDR to be known as The Ulster Defence Regiment CGC.