ṬHĀKUR SIṄGH SANDHĀṄVĀLĪĀ (1837-1887), one of the founders of the Siṅgh Sabhā and a scion of the Sandhāṅvālīā family, who master-minded the campaign for the restoration of Mahārājā Duleep Siṅgh to the throne of the Punjab, was son of Lahiṇā Siṅgh, who in the reign of Mahārājā Raṇjīt Siṅgh enjoyed the title of Ujjal-dīdār, Nirmal buddh, Sardār-i-bā-waqār (resplendent presence, pure of intellect, the Sardār with prestige marked). Born in 1837, in a Punjab which was soon to fall into chaos as a result of courtly intrigue and murder, Ṭhākur Siṅgh was a mere child of six at the time of his father's death. As he grew up, he was given appointment by the British as extra assistant commissioner for Amritsar district. He was also nominated a member of the Golden Temple managing committee. In this capacity, he observed how Sikh religion had been corrupted by the accretion of customs and rituals contrary to the teachings of the Gurūs. He also felt concerned about the general state of the Sikh community. In 1873, occurred an event which gave a decisive turn to his career. Four Sikh pupils of the Mission High School in Amritsar declared their intention of abjuring their faith in favour of Christianity. Ṭhākur Siṅgh called in Amritsar a meeting of some of the leading Sikhs of the day, including Bābā Sir Khem Siṅgh Bedī, a descendant of Gurū Nānak, Kaṅvar Bikramā Siṅgh of Kapūrthalā, and Giānī Giān Siṅgh of Amritsar. This Sikh meeting laid the foundation of a society called the Srī Gurū Siṅgh Sabhā.
Ṭhākur Siṅgh became the first president of the Siṅgh Sabhā. Apart from religious reform among the Sikhs, the Siṅgh Sabhā ushered in a new cultural consciousness in the Punjab. It aimed especially at the development of modern education. ṭhākur Siṅgh remained at the helm of affairs of the new society for a whole decade. He was a distinguished scholar of Persian and Punjabi, well versed in Indian as well as in Muslim lore.
Because of his independent views, Ṭhākur Siṅgh was deprived of his position as extra assistant commissioner. In 1883, his estate was placed under a court of wards. The same year he received from Mahārājā Duleep Siṅgh living as a ranked British noble in London after being deprived of the throne of the Punjab, a wire inviting him.
Before his departure for England in 1884, Ṭhākur Siṅgh visited the Takhts, the principal Sikh shrines--at Amritsar, Anandpur, Paṭnā and Nānḍeḍ--to pray for the prosperity of Duleep Siṅgh’s cause. Accompanied by two of his sons, Narindar Siṅgh and Gurdit Siṅgh, a granthī or Scripture-reader, Partāp Siṅgh, and three servants, he reached London, where he stayed as the guest of Mahārājā Duleep Siṅgh. He daily read out from the holy Gurū Granth Sāhib to the Mahārājā and instructed him in the tenet of Sikhism. Under his influence, Duleep Siṅgh determined to rejoin the faith of his forefathers.
In August 1885, Ṭhākur Siṅgh returned to the Punjab. Duleep Siṅgh himself decided to return to his motherland and left England on 31 March 1886 to settle down quietly in Delhi. He invited Ṭhākur Siṅgh to meet him at Bombay and arrange for his reinitiation into Sikhism, but the government refused him permission to go to Bombay. Furthering the cause of Duleep Siṅgh was now Ṭhākur Siṅgh's sole concern. To win support for him, he sited secretly the Indian princely states and the Sikh shrines. Major Evans Bell's book, The Annexation of the Punjab and the Maharajah Duleep Singh, exhibiting the illegality of British occupation of the Punjab, was widely circulated. Ṭhākur Siṅgh had the book translated into Punjabi by his friend Partāp Siṅgh, the granthī and published by another supporter, Dīwān Būṭā Siṅgh, of Aftāb-i-Punjab Press.
Ṭhākur Siṅgh was now the most suspicious character in the eyes of the government. In intelligence reports and other government papers, he was described as "a troublesome person… the friend and inciter of Duleep Singh." Yet he made good his escape into Pondicherry on 6 November 1886. His home in the Rue Law de Lauristan became the centre of activity against the British. Ṭhākur Siṅgh received correspondence from Duleep Siṅgh through the French post office. Through the same medium he sent to him his letters and the Indian newspapers such as The Times of India and Madras Times. He laid out a fairly extensive system of communication in the Punjab, and had a continuous stream of visitors in Pondicherry including, occasionally, soldiers from the Indian Army.
Envoys came from Duleep Siṅgh as well. From Russia, he sent to Ṭhākur Siṅgh a seal and letter in token of his appointment as prime minister to his emigre government. But the latter had not long to live. He suddenly fell ill and died on 18 August 1887. His ashes were taken to his ancestral village of Rājā Sāṅsī. His sons continued to live in Pondicherry the eldest, Gurbachan Siṅgh, receiving from Duleep Siṅgh the title of prime minister.