British Army: Principal land warfare force of the United Kingdom, a part of British Armed Forces

The British Army came into being with unification of the Kingdoms of England and Scotland into the Kingdom of Great Britain in 1707. The new British Army included regiments that had already existed in England and Scotland and was administered by the War Office from London. Since 1963, it has been managed by the Ministry of Defence. Around a quarter of soldiers in the British Army are in the Infantry.

Under Oliver Cromwell, the English Army was active in the conquest and settlement of Ireland since the 1650s. The Cromwellian campaign was characterised by its uncompromising treatment of Irish towns that had supported the Royalists during the English Civil War.

Since the Seven Years' War ebded in 1763, the British have been one of the leading military and economic powers of the world. The British Empire expanded to include colonies, protectorates, and dominions throughout the Americas, Africa, Asia and Australasia. Although the Royal Navy is widely regarded as having been vital for the rise of the empire and British dominance of the world, the British Army also played important roles in colonisation.

The British Army was heavily involved in the Napoleonic Wars by serving in Spain and the rest of Europe and in North Africa. The war between the British and the French Empires stretched around the world. The British Army finally came to defeat Napoleon at one of Britain's greatest military victories at the Battle of Waterloo.