[4] To this end he negotiated an agreement with Wazir Akbar Khan, one of the sons of Dost Mohammad Barakzai, by which his army was to fall back to the Jalalabad garrison, more than 140 kilometres (90 mi) away.

[5] Out of more than 16,000 people from the column commanded by Elphinstone, only one European (Assistant Surgeon William Brydon) and a few Indian sepoys reached Jalalabad.

"[11] In 1838 the East India Company feared an increased Russian influence in Afghanistan after Dost Mohammad Barakzai had seized power from former ruler Shuja Shah Durrani in 1834.

Dost Mohammad had rejected earlier overtures from Russia, but after Lord Auckland, the Governor-General of India, tried to force Afghan foreign policy under British guidance, he renewed his relationship with the Russians.

They advanced through rough terrain, crossing deserts and mountain passes at an elevation of 4,000 metres (13,000 ft) but made good progress and took Kandahar on 25 April.

This decision, made on diplomatic grounds, would prove to be a grave military error that placed the whole garrison in a weak and easily overrun position.

[16] Britain had replaced Dost Mohammad, a (relatively) popular ruler, with Shuja Shah, a weak puppet, who was seen as far crueler to his enemies than his predecessor.

In 1840, the son of Dost Mohammad, Wazir Akbar Khan, began assembling allies amongst the tribesmen in the rural areas where British influence was weakest.

Although Elphinstone was a man of high birth and perfect manners, his colleague and contemporary General William Nott regarded him as "the most incompetent soldier that was to be found amongst all the officers of requisite rank".

A British force sallied out to drive them away, but the Afghans drove them back with jezail fire at long range from the high ground.

[21] Elphinstone sent messengers to request help from Major General Nott in Kandahar, but they turned back when they found the mountain passes blocked by heavy snow.

Macnaghten, realising their desperate situation, tried to negotiate an agreement with Akbar Khan for the withdrawal of the troops and the 12,000 British and Indian civilians living in Kabul.

[22] The moment his party dismounted from their horses, they were seized and Macnaghten and an aide were slain by armed men; their bodies were mutilated and dragged through the streets of Kabul.

[2] At first light on 6 January Elphinstone's column began slowly to move out of Kabul leaving Shuja Shah Durrani and his followers to their fate.

[24] On leaving the city, Elphinstone discovered that the escort promised by Akbar Khan had not materialised, nor had the food and fuel to help with the crossing of the Hindu Kush in winter.

[25] Major Eldred Pottinger pleaded with the sick British commander to turn back to Kabul as they still had time to take refuge in the fortress of Bala Hissar.

Akbar Khan then asked Elphinstone to wait while he negotiated the column's safe passage with the Afghan chiefs who commanded Khord-Kabul pass 25 kilometres (15 mi) from Kabul.

When the column entered the narrow six-kilometre (four-mile) pass the next day, they were shot at from all sides by Ghilzais armed with captured British muskets and their traditional jezails.

A written report by Elphinstone recorded that most of the sepoys had by this stage lost fingers or toes in the freezing conditions, and that their snow-encrusted muskets had become unusable.

On the evening of 9 January, Lady Sale, along with the wives and children of both British and Indian officers, and their retinues, accepted Akbar Khan's assurances of protection.

As the surviving troops lay besieged in a small ruined mud-walled enclosure in Jagadalak, Akbar Khan's envoys returned and persuaded Elphinstone and his second in command, Shelton, to accompany them for negotiations.

The remaining troops, now led by Brigadier-General Thomas John Anquetil, found their path blocked by a formidable thorny barrier of 'prickly holly oak, well twisted together, about six feet high' which had been erected across the narrowest part of the valley.

[31] The biggest single surviving group of men, consisting of 20 officers and 45 European soldiers, mostly infantry from the 44th Regiment of Foot, tried to press on but found themselves surrounded on a snowy hillock near the village of Gandamak.

[33] On 13 January, a British officer from the 16,000 strong column rode into Jalalabad on a wounded horse (a few sepoys, who had hidden in the mountains, followed in the coming weeks).

After escaping a single pursuer, he was spotted by a staff officer on the walls of Jalalabad who immediately dispatched riders to meet the exhausted surgeon.

[6] The annihilation left Britain and India in shock and the Governor General, Lord Auckland, suffered an apparent stroke[34] upon hearing the news.

In the autumn of 1842, an "Army of Retribution" led by Sir George Pollock, with William Nott and Robert Sale commanding divisions, leveled the great bazaar and all the larger buildings of Kabul.

Elphinstone completely failed to lead his soldiers, but fatally exerted enough authority to prevent any of his officers from exercising proper command in his place.

The destruction of several regiments of Indian troops during the retreat inevitably affected the morale of the East India Company's Bengal Army from which these units had been drawn.

In the show, Queen Victoria responds to the loss of life in the retreat with a speech at the launch of HMS Trafalgar, and by privately meeting and honouring Brydon.