CPI-M politburo member and state secretary Biman Bose emerged from the hospital at 12:12 pm weeping to formally announce the passing away of 95-year-old Basu.
"I have a sad announcement to make. Our beloved leader Jyoti Basu is no more."
Union Home Minister P Chidambaram, Chief Minister Buddhadeb Bhattacharjee, former Lok Sabha speaker Somnath Chatterjee and a host of Left Front leaders were present at the hospital. CPI-M General Secretary Prakash Karat and Brinda Karat were also there.
The road leading to the hospital at Salt Lake was closed to traffic by the police who were deployed in large numbers.