Moving through the land mostly by political care, and paying local khans to support them, they moved into the mountains to fight an essentially punitive campaign against the Pashtun tribes, in response to repeated brutal armed raids on the villages of the Plains of India. Crops were burnt, wells were filled with stone and houses burnt, and the occasional firefight broke out in the mountains. This campaign effectively neutralised the aggressors for several decades.
Churchill makes some observations about fanaticism of the tribal warriors:
Every influence, every motive, that provokes the spirit of murder among men, impels these mountaineers to deeds of treachery and violence. The strong aboriginal propensity to kill, inherent in all human beings, has in these valleys been preserved in unexampled strength and vigour. That religion, which above all others was founded and propagated by the sword--the tenets and principles of which are instinct with incentives to slaughter and which in three continents has produced fighting breeds of men--stimulates a wild and merciless fanaticism.
The Indian government was concerned about where the frontier of India should be. The Russian frontier had advanced in a few decades to the Pamirs, and there was real concern that a force of cossacks could traverse the Hindu Kush and invade India. To resist this the Forward Policy held that the passes should be held by the Indian government through its vassals. A recent uprising in Chitral, arising from a series of dynastic murders, had more or less accidentally led to a campaign to relieve the British garrison there. In the aftermath of the campaign a substantial force held the road, based at the Malakand, and subsidising local rulers. The peaceful conditions improved the lot of the Pashtuns, but eventually an uprising occurred, and the camp was attacked.
The attacks were beaten off, but a force was assembled under Sir Bindon Blood to punish the aggressors, many of whom had come out of Swat and Bunerwal which had not felt the force of British power and were spoiling for a fight. A young Winston Churchill arranged to be attached to the force.
His experiences in this campaign meant that, unlike most military thinkers of the time, he could better understand the stalemate of WWI trench warfare. This undoubtedly influenced his choice to invest government research and funds into the development of the tank via the Landships Committee when he was First Lord of the Admiralty.