When Bhimrao Ramji Ambedkar was a schoolboy, he was not allowed to drink from the same tap as his fellow students because he was a member of what was then known as an "untouchable" caste. But he went on to become a prominent leader in the campaign for Indian independence and oversaw the writing of the Indian constitution - which made the idea of "untouchability" illegal. A hero to many, he died in December 1956.Lucy Burns hears recordings of BR Ambedkar from the BBC archives and speaks to biographer Ananya Vajpeyi.Picture: A member of the Indian Congress Party places flowers on a statue of BR Ambedkar to mark the 122nd anniversary of his birth in Amritsar on April 14, 2013 (NARINDER NANU/AFP/Getty Images)