The Territorial Army, or TA, is the reserve component of the British Army, the main land-based military force of the United Kingdom. It can be seen as equivalent to the United States National Guard. Territorial Army soldiers and officers are paid at the same rate as their Regular Army equivalents, but serve part-time (usually with a minimum commitment of 27 days per year). The annual budget of the Territorial Army is approximately £350 million – around 1.3% of the total defence budget for the United Kingdom. As of 2006, the TA had a strength of approximately 34,000.
The TA was established in 1908 by the then-Defence Secretary, Viscount Haldane. It united the existing militia, Yeomanry and Volunteer Force units into a single force.
Following the First World War, all Territorial Army units were gradually disbanded; however, the force was re-established from 1920 onwards. In 1922 two Air Defence Brigades were established to provide anti-aircraft defence for London. In 1939, with the outbreak of the Second World War, the size of the TA was doubled, and many TA units were deployed overseas and served with distinction.
Post-war, the TA was drastically reduced in size with the ending of conscription in 1960. In 1967 it was renamed the "Territorial Army and Volunteer Reserve" and the regimental structure was abolished, but these changes were reversed in 1979.
Today the TA does not generally supply complete combat divisions; instead, it supplies smaller units of up to battalion size which serve alongside Regular Army Units, in a variety of roles including infantry, reconnaissance, light artillery, and support roles such as engineering, medical, or military police.
The TA did not play a major role in overseas conflicts throughout the Cold War; this was because it was not possible, legally, to compulsorily deploy individual TA personnel or units overseas, only the whole Territorial Army (which only took place during major wars). As such, their primary role was home defence during this era. However, in 1996, the new Reserve Forces Act allowed individual TA personnel and units to be called up for overseas service, except those in full-time education or who have exemption on certain compassionate grounds. As a result, 9,500 reservists were called up for the invasion of Iraq in 2003, and today some 1,200 TA personnel are deployed in the field each year to Iraq, Afghanistan and other theatres.