Even as several Congress leaders defended Manmohan Singh on the 2G issue, former Union Minister Kamal Nath said the former Prime Minister may have made a “mistake” in not acting despite his letter to him expressing concern over the spectrum allocation process. “He may have made a mistake. I would go along with you. I brought it to his notice. He did not understand the import” and he did not act, Nath said to a question whether the then Prime Minister had made a mistake. “I was disappointed that the Prime Minister did not act.... In retrospect and hindsight, gravity and magnitude was not known. It was not known to me and the PM. It is very unfair to say that he knew everything,” he told a TV channel.