"I have rarely seen anybody have the level of integrity she has. She works for the people day and night. She has a lot of love and affection for the people who are like family to her," Katju said at a programme here.
Drawing a parallel between her and former state chief minister B C Roy, he said "Banerjee has the potential to become another B C Roy whom people will remember in the times to come."
On the criticism she is facing on a number of issues, Katju described it as being "unfair" to her.
"Everybody makes mistakes. Her qualities far outweigh her mistakes. Everybody has defects," the former Supreme Court judge said.
