Returning to Calcutta, he was appointed to take charge of the secret and political departments and held that post for four years. In 1838, he headed a mission to the Sikh capital which led to the signing, on 26 June 1838, of the Tripartite treaty. Macnaghten's mission to Lahore was undertaken in view of the growing Russian influence in Persia and Afghanistan and the supposed threat to the British possessions in India. Auckland's government had decided to subvert the power of Amir Dost Muhammad Khan and to restore ex-king Shah Shuja' to the throne at Kabul with the help of Sikh arms and British money. Maharaja Ranjit Singh was agreeable to Macnaghten's proposals, but laid down certain conditions.
Among other things, he demanded a perpetual tribute or subsidy of 2,00,000 rupees to be paid annually by Afghanistan to the Sikhs, a compensation for forgoing claims on Shikarpur and Sindh, and the cession of the district of Jalalabad and its dependencies to him. All the demands of the Maharaja except the cession of Jalalabad were agreed to by Macnaghten. After the restoration of Shah Shuja' in 1839 in which the Sikh forces did not take part in any military operations beyond the Khaibar, Sir William was appointed the British ministerand envoy to Kabul.
Amidst mounting disagreements between the Sikhs and the English, particularly on the Sikh-Afghan borders and the two frontier territories of Swat and Buner, Macnaghten made wild accusations against the Sikh Darbar. He demanded the recall of the Sikh governor of Peshawar, General Avitabile, who, he alleged, was coercing the Khaibaris and extending Sikh influence beyond their borders. He complained that the Peshawar Barakzai tributaries of the Sikh government were giving asylum to the Gilzaic chiefs, the rebel Afghan subjects. Macnaghten finally contended that after the death of Ranjit Singh, the Tripartite treaty had lapsed and proposed that the Sikhs restore to the Afghans their former territories on the Indus, including Peshawar. On 23 December 1841, Sir William Macnaghten was lured by the Afghans into a conference and assassinated by Prince Akbar Khan, the deposed Amir's son.
1. Banerji, A.C., Anglo-Sikh Relations. Calcutta, 1949
2. Hasrat, B.J., Anglo-Sikh Relations (1799-1849). Hoshiarpur, 1968
3. Buckland, C.E., Dictionary of Indian Biography. London, 1906