To justify his plan, Auckland ordered a manifesto issued on October 1, 1838, at Simla that set forth the reasons for British intervention in Afghanistan. The Simla Manifesto stated that the welfare of India required that the British have on their western frontier a trustworthy ally. The British pretense that their troops were merely supporting the tiny force of Shuja in retaking what was once his throne fooled no one. Although the Simla Manifesto asserted that British troops would be withdrawn as soon as Shuja was installed in Kabul, Shuja's rule depended entirely on British arms to suppress rebellion and on British funds to pay tribal chiefs for their support. Like other interventions in modern times, the British denied that they were invading Afghanistan but claimed they were merely supporting its legitimate government (Shuja) "against foreign interference and factious opposition."
From the point of the view of the British, the First AngloAfghan War (often called "Auckland's Folly") was an unmitigated disaster, although it proved surprisingly easy to depose Dost Mohammad and enthrone Shuja. An army of British and Indian troops set out from the Punjab in December 1838 and by late March 1839 had reached Quetta. By the end of April the British had taken Qandahar without a battle. In July, after a two-month delay in Qandahar, the British attacked the fortress of Ghazni, overlooking a plain that leads to India, and achieved a decisive victory over the troops of Dost Mohammad, which were led by one of his sons. The Afghans were amazed at the taking of fortified Ghazni, and Dost Mohammad found his support melting away. The Afghan ruler took his few loyal followers and fled across the passes to Bamian, and ultimately to Bukhara, and in August 1839 Shuja was enthroned again in Kabul after a hiatus of almost 30 years. Some British troops returned to India, but it soon became clear that Shuja's rule could only be maintained by the presence of British forces. Garrisons were established in Jalalabad, Ghazni, Kalat-iGhilzai (Qalat), Qandahar, and at the passes to Bamian. After a winter in temporary quarters, the British thought to move their Kabul garrison to the great fort, Bala Hissar, overlooking the city, but Shuja, either on his own or under pressure, refused to sanction the move.
Omens of disaster for the British abounded. Opposition to the British-imposed rule of Shuja began as soon as he assumed the throne, and the power of his government did not extend beyond the areas controlled by the force of British arms. The British cantonment in Kabul was eventually constructed on a virtually indefensible open plain northeast of the city, with the commissariat and munitions outside the low walls of the garrison. Early in 1841 a new commander, who was elderly, ill, and indecisive, joined the British troops in Afghanistan.
After several attacks on the British and their Afghan protege Dust Mohammad decided to surrender to the British and in late 1840 was allowed to go into exile in India. Sir William Macnaghten, one of the principal architects of the British invasion, wrote to Auckland two months later, urging good treatment for the deposed Afghan leader. With that fairness and clearsightedness that, in retrospect, was characteristic of British colonial officials, Macnaghten said:
His case has been compared to that of Shah Shoojah . . . but surely the cases are not parallel. The Shah [Shujal] had no claim on us. We had no hand in depriving turn of his kingdom, whereas we ejected the Dost, who never offended us, in support of our policy, of which he was the victim.
Dual control (by Shuja and the British) was unworkable. Shuja did not succeed in garnering the support of the Afghan chiefs on his own, and the British could not-or would notsustain their subsidies. When the cash payments to tribal chiefs were curtailed in 1841, there was a major revolt by the Ghilzai.
By October 1841 disaffected Afghan tribes were flocking to the support of Dost Mohammad's son, Muhammad Akbar, in Bamian. Barnes was murdered in November 1841, and a few days later the commissariat fell into the hands of the Afghans. Macnaghten, having tried first to bribe and then to negotiate with the tribal leaders, was killed at a meeting with the tribal chiefs in December. On January 1, 1842, the British in Kabul and a number of Afghan chiefs reached an agreement that provided for the safe exodus of the entire British garrison and its dependents from Afghanistan. Unfortunately, the British would not wait for an Afghan escort to be assembled, and the Ghilzai and allied tribes had not been among the 18 chiefs who had signed the agreement. On January 6 the precipitate retreat began and, as they struggled through the snowbound passes, the British were attacked by Ghilzai warriors. Although a Dr. W. Brydon is usually cited as the only survivor of the march to Jalalabad (out of more than 15,000 who undertook the retreat), in fact a few more survived as prisoners and hostages. Shuja remained in power only a few months and was assassinated in April 1842.
The destruction of the British garrison prompted brutal retaliation by the British against the Afghans and touched off yet another power struggle among potential rulers of Afghanistan. In the fall of 1842 British forces from Qandahar and Peshawar entered Kabul long enough to rescue the British prisoners and burn the great bazaar. All that remained of the British occupation of Afghanistan was a ruined market and thousands of dead. Although the foreign invasion did give the Afghan tribes a temporary sense of unity they had lacked before, the accompanying loss of life and property was followed by a bitterness and resentment of foreign influence that lasted well into the twentieth century and may have accounted for much of the backlash against the modernization attempts of later Afghan monarchs. The Russians advanced steadily southward toward Afghanistan in the three decades after the First Anglo-Afghan War, and historians of the period generally agree that the Russians were motivated, at least in part, by British intervention in Afghanistan. In 1842 the Russian border was on the other side of the Aral Sea from Afghanistan, but five years later the tsar's outposts moved to the lower reaches of the Syr Darya. By 1865 Tashkent had been formally annexed, as was Samarkand three years later. A treaty with the ruler of Bukhara virtually stripped him of his independence, and by 1869 Russian control ran as far as the northern bank of the Amu Darya. As the Russians overran much of Central Asia north of the river, the British advanced toward Afghanistan as well, absorbing territories that had once been part of Ahmad Shah Durrani's empire: Sind in 1843, Kashmir in 1846, the Punjab in 1849, Baluchistan in 1859, and the North-West Frontier in 1895.