First Anglo-Afghan War: Worst Military Defeat In British Imperial History

Background: The First Anglo-Afghan War 1839-1842
The First Anglo-Afghan War is widely considered the worst military defeat in British Imperial history. Also known as Auckland's Folly, it was a contest between the British East India Company and the tribes of Afghanistan from 1839 to 1842. Approximately 4,500 British and Indian Sepoy soldiers, and 12,000 camp followers died in the ruinous retreat from Kabul through the Gandamak Pass to Jalalabad. Famously (if exaggeratedly) only one British survivor, assistant surgeon William Brydon, made it to Jalalabad on 13 January 1842. History ultimately remembers the war as a grave misstep, even though the British defeated the Afghan tribesmen in the following engagement, and managed to achieve their
Dost Mohammad was reluctant to enter into an official alliance with Great Britton, but would not enter into one with the Russians either. Burnes advised Lord Auckland, Governor-General of India, to leave Dost Mohammed as the sovereign of Afghanistan. Sir William Hay Macnaghten, chief secretary of the Calcutta government, swayed the opinion of Lord Auckland, however, to reinstate the exiled King Shah Shuja. This was the first failure of intelligence on the part of the British. Had Lord Auckland listened to the advice of Alexander Burnes, the very intelligence asset that he had dispatched in the first place, the British would have effectively blocked Russian incursion into Afghanistan at far smaller cost (more on the actual cost
Rather than the standard tradition of levying forces from the tribal warrior chiefs in exchange for cash remittances, the British created a modern uniformed military force lead by British officers in much the same mold as Indian colonial units. This allowed for the dismissal of the traditional tribal military chiefs, which was looked upon at the time as a pleasant second order effect. The almost unforeseen third order effect was that Shah Shuja was robbed of the very mechanism by which he was able to maintain tribal loyalty. I say almost unforeseen, because Shah Shuja himself informed Macnaghten of this fact. Macnaghten, in his now trademark condescending style, dismissed this out of hand. These very same men, and their forces, would go on to fight in rebellion against the British just a short time later (Barfield 2010).
To the credit of the British, this was not done for the sake of making Shah Shuja more reliant on them, and thus more pliable, they simply did it because they considered it a moral obligation to provide good governance. However, good governance in Afghanistan looked very different from good governance in British India. This can be counted as the first failure of intelligence during the occupation. Very clear human intelligence (HUMINT) reporting, in the form of concerns expressed by the very sovereign that the British put in place, indicated that the disbanding of the tribal