Within the party, too, he has often had a difficult time with the state party secretary Promode Das Gupta, the Bengal strongman who has made the CPI(M) what it is today. Das Gupta once threatened to arrest Union Home Minister S.B. Chavan if he came to Calcutta. Basu's work was cut out in Delhi in trying to explain Das Gupta's blunt remark. Then again, when Indira Gandhi was prime minister, she is said to have told Basu: "I do not doubt your credentials or sincerity, but I am less sure about some of your colleagues in your party", obviously referring to Das Gupta.
"Our party believes in revolution. While we participate in parliamentary politics, it is our intention to expose the basic hollowness of the system which cannot usher in fundamental social changes," Basu has emphasised time and again in his articles in the party mouthpiece, Ganashakti, and in his speeches. His critics, the Naxalites for instance, see his kind of politics as leading straight to the "sunlit plateau of social democracy"—to use a phrase coined by the late S.A. Dange—that had little to do with armed revolution. To his credit, Basu has been honest. Once, an ideologically confused cadre felt that the CPI(M) was going 'soft'. He agonised over his dilemma and met many ideologues, but to no avail. Basu took matters in hand and in his three-minute 'meeting' with the disillusioned youth he told him: "If you really believe that now is the time for a revolution, better join one of the Naxalite factions. If not, it is for you to decide whether you will stay with us. Either way, it is your decision." The young man, who is still with the CPI(M), says: "He did reduce my problem in his blunt and forthright manner. It made a lot of sense to me."
This unique ability, coupled with a remarkable courage—in 1969, he shooed off an angry mob of armed policemen, who had attacked the state assembly after a revolt, as ministers and others scurried for shelter—has enabled Basu to cover a larger political distance in his career than more ideology-bound colleagues.
On the last leg of his political career, Basu is often rude to the press, occasionally lashes out at political opponents, and has frequent outbursts of temper. But these failings apart, history will not be able to rank him lower than Promode Das Gupta, often called "the best communist organiser in South Asia".