After 1949, members of the right-wing Hindu nationalist Rashtriya Swayamsevak Sangh (RSS) began to contemplate the formation of a political party to continue their work, begun in the days of the British Raj, and take their ideology further. Around the same time, Syama Prasad Mukherjee left the Hindu Mahasabha political party that he had once led because of a disagreement with that party over permitting non-Hindu membership. The BJS was subsequently started by Mukherjee on 21 October 1951 in Delhi, with the collaboration of the RSS, as a "nationalistic alternative" to the Congress Party.