Sapru and Indian Liberals collaborated with the Congress after the ascent of Mahatma Gandhi, who advocated non-violent civil disobedience against British rule.

Chimanlal Setalvad from Bombay was also present ready to co-operate with Muslims M. A. Jinnah, and M. R. Jayakar, alongside C. P. Ramaswami Aiyer from Madras.

[5] Kailas Nath Haksar was a personal friend who also proposed federation of British and princely India, responsibility was a conservative counter-weight to radicalisation.

They established good relations with the British Ministry of Works and Gandhi to build a forum for the round table conference.

The factional splits were fatal to the princes cause; and Sapru's severe criticisms of Maharaja of Dhollpur only served to postpone federation.

The bureaucratic denials slowed attempts, and so in early 1932 Lord Lothian of the Franchise Committee made overtures towards Federation, they recruited Hailey's organ The Pioneer to persuade the princes to donate.

Sapru mediated between Gandhi and the Viceroy Lord Irwin, helping to forge the Gandhi–Irwin Pact that ended the Salt Satyagraha.

[citation needed] Sapru also mediated between Gandhi, B. R. Ambedkar and the British over the issue of separate electorates for India's "Untouchables", which was settled by the Poona Pact.

But by Third Round Table many princes would not turn up, and their ministers were lukewarm about federation, and personalities clashed to exclude his able lieutenant Haksar.

Sapru was also one of the main lawyers engaged to defend captured soldiers of the rebel Indian National Army, raised by nationalist leader Subhas Chandra Bose with the aid of Imperial Japan during the war[citation needed]and the Quit India Movement (1942–46).

[citation needed] Sir Tej Bahadur Sapru died on 20 January 1949 in Allahabad, seventeen months after India gained independence.