In their attempts to assert control in India, the British faced fierce resistance in some regions while easily conquering others. British officials sought 'martial races' accustomed to hunting, or from agricultural cultures from hilly or mountainous regions with a history of conflict. Others were excluded due to their 'ease of living' or branded as seditious agitators. The doctrine of 'martial races' postulated that the qualities that make a useful soldier are inherited and that most Indians, with the exception of the specified groups, did not have the requisite traits that would make them warriors.
The British recruited heavily from the 'martial races' for service in the colonial army. Sensing the inequalities and fierce loyalty to one's tribe or group of the diverse native peoples of the subcontinent, the British found opportunities to use it to their own great advantage. These already wide divides were a fertile breeding ground to inculcate pride in one's identity based on 'race'. This served the British in two ways. On the one hand it made sure that there was no repetition of the Indian rebellion of 1857 by ensuring there was no unity among the different subjects of the Raj. On the other hand, it encouraged a sense of competition among the different 'races'.
British general and scholar Lieutenant-General Sir George MacMunn (1869–1952) noted in his writings "It is only necessary for a feeling to arise that it is impious and disgraceful to serve the British, for the whole of our fabric to tumble like a house of cards without a shot being fired or a sword unsheathed". To this end, it became British policy to recruit only from those tribes whom they classified as members of the 'martial races', and the practice became an integral part of the recruitment manuals for the Army in the British Raj. According to Jeffrey Greenhut, "The Martial Race theory had an elegant symmetry. Indians who were intelligent and educated were defined as cowards, while those defined as brave were uneducated and backward."
The British regarded the 'martial races' as valiant and strong but also intellectually inferior, lacking the initiative or leadership qualities to command large military formations. They were also regarded as politically subservient or docile to authority. For these reasons, the martial races theory did not lead to officers being recruited from them; recruitment was based on social class and loyalty to the British Raj. One source calls this a "pseudo-ethnological" construction, which was popularised by Frederick Sleigh Roberts, and created serious deficiencies in troop levels during the World Wars, compelling them to recruit from 'non-martial races'. Winston Churchill was reportedly concerned that the theory was abandoned during the war and wrote to the Commander-in-Chief, India that he must, "rely as much as possible on the martial races". After Indian Independence, the Indian Army abandoned this theory and recruitment took place without discrimination.
Critics of the theory state that the Indian rebellion of 1857 may have played a role in reinforcing the British belief in it. During this event the troops from the Bengal Native Infantry led by sepoy Mangal Pandey mutinied against the British. However, the loyal Pashtuns, Punjabis, Gurkhas, Kumaoni/Kumaunis and Garhwalis did not join the mutiny, and fought on the side of the British Army. From then on, this theory was used to the hilt to accelerate recruitment from among these 'races', whilst discouraging enlistment of 'disloyal' troops and high-caste Hindus who had sided with the rebel army during the war.