"Gandhi is the greatest enemy the untouchables have ever had in India." -- http://en.wikipedia.org/wiki/Ambedkar
Now there is 49.5% reservation now in educational institutions in India, yes 49.5% !!, because that's the highest allowed by the constitution, otherwise they would have gone higher. It's something similar to "affirmative action" in the US, but totally taken over by politicians to play electoral politics, to pump in the votes from the lower sections of society.
Gandhi had the vision to understand that caste-based reservations would lead to caste-based politics and further affirmation of casteism in India, Ambedkar never could fathom that, or maybe he could and ignored it!
Anyway, please don't quote someone who didn't understand the ideas or vision of Gandhi, please don't.
sources - http://books.google.co.in/books?id=RAON5AW4yUEC&pg=PA232...
Ok, Here goes.
"Abandoning all these sober considerations Mr. Gandhi came out as an, open enemy of the Untouchables. How can the Untouchables regard such a man as their friend and ally?"
http://www.ambedkar.org/ambcd/41K.What%20Congress%20and%20Ga...
"Thus ended the efforts by the Minorities Committee to bring about a solution of the communal problem. The discussion in the Committee threw Mr. Gandhi's attitude to the Untouchables in relief. Everybody felt that Mr. Gandhi was the most determined enemy of the Untouchables."
http://www.ambedkar.org/ambcd/41D.What%20Congress%20and%20Ga...
Not literally the same statement, but similar in sentiment. Google is your friend.
That Ambedkar regarded Gandhi is a pious fraud and hypocrite is well known to students of Indian History. That doesn't make Gandhi an "enemy of the untouchables" , but yes Ambedkar thought so at times, and said so at times.