"He (Mandela) said we were mirrors that he could look into whenever he needed to be criticised, because we could criticise him. But the only clash we ever had was in 1950, and it was quite serious," Kathrada told PTI.
"There was a strike organised by the South African Indian Congress (ANC) and the Communist Party, which was successful although 18 people were killed.
Kathrada said at that time the policy of the ANC Youth League was that it was for Africans only, which was not racist but exclusionist.
"Mandela and I got into an argument about it. He was 11 years my senior and I challenged him, debating the issue. He was quite angry about it and complained about me - he took it quite seriously and raised it at a joint meeting of SAIC and Ismail Meer asked him to dismiss it because of my youth," 85-year-old Kathrada said.
"After that we always joked about it in jail, when I told him I had won that debate."
Kathrada's most enduring memory of his friendship with Mandela is his very first meeting with him in the late 1940s. "There were very few Indians at the University. I knew Ismail Meer and JN Singh who were both doing law at Wits and Madiba was their fellow law student. Ismail was staying at Kholvad House (in Central Johannesburg), where I was staying too and Madiba came there with them after law studies.
"It was the first time I met an African chap who was a law student. I was in awe of this man who was a university student and the abiding memory was how he was able to relate to me as a youngster. He made me feel his equal by the type of questions he asked me about myself," Kathrada said.
"It made me feel so comfortable and proud... I could go back to school and boast that I met a university student!"
Commenting on the time they spent together on Robben Island jail, Kathrada said the morale of all the prisoners was always boosted by Mandela's actions.
"When we arrived on the island, his first communication with us was to say that we were no longer leaders, we were ordinary prisoners, we don't make policy we don't give orders to those outside. He behaved as an ordinary prisoner, washing dishes, dishing up food, carrying out toilet buckets for people who were ill, polished his cell and on hunger strike with others, refusing to be exempted as a senior," he added.