THIRUVANANTHAPURAM/KOLKATA: Jyoti Basu, the charismatic Indian Marxist who headed the world’s most electorally successful communist party for two decades, died on Sunday at the age of 95.

Basu’s death is seen as a possible blow to unity among a disparate group of communists facing a tough election next year in the eastern state of West Bengal, a traditional leftist stronghold.

Basu died from multiple organ failure at a city hospital, where tens of thousands of his admirers gathered, many teary-eyed. Others raised their hands in a Soviet-style salute as Basu’s body was carried in a hearse to a city mortuary.

“The passing away of Basu from the scene marks the end of an era in the annals of Indian politics,” India’s Prime Minister Manmohan Singh said in a statement.

The communist-ruled southern state of Kerala canceled all official functions for three days following Basu’s death on Sunday. Party flags were flying at half-staff with a black banner on top at the AKG Center, the state headquarters of the Communist Party of India-Marxist (CPM).

Chief Minister V.S. Achuthanandan, a central committee member of the CPM, canceled all his official functions till Wednesday. He said he would be catching the first flight to Calcutta Monday. “Comrade Basu’s death is a great loss for me personally. He was the most senior member in our party and we have lost the biggest revolutionary of our era,” the 87-year-old leader said in his condolence message.

India’s Defense Minister A.K. Antony, a former chief minister of Kerala, said Basu was a towering leader and the biggest contribution of the communist movement to the nation.

A London-trained barrister, Basu entered politics as a union leader and gained fame leading West Bengal for almost a quarter century, the longest-serving chief minister in Indian political history. He stepped down in 2000 because of failing health.

While Basu’s rule was credited with bringing stability to West Bengal, he was blamed for allowing the economy to stagnate, often at the hands of militant trade unions opposing even the use of computers in government offices for fear of job losses.

Basu retired from active politics a decade ago, but his towering stature retained its unifying influence among the leftist groups and he continued to play the role of crisis manager and political arbitrator.

Kshiti Goswami, a West Bengal minister and a coalition ally, said it would be difficult to maintain the leftist coalition without the charismatic leader.

After an inconclusive general election in 1996, Basu was within a hair’s breadth of becoming prime minister at the head of a center-left coalition — a prospect that prompted the headline “Red Star Over Delhi” in one national newspaper. But the CPM’s central committee decided not to participate in the government — a move that Basu later described as a “historic blunder” in an open criticism of a section of his party’s dogmatic ideologues.

The son of a well-off Bengali family, Basu was born in 1914 in Kolkata, which was then the capital of British India.

While training to be a lawyer in England in the 1930s, at the time of the Spanish Civil War and the rise of fascism, he was drawn to the communist movement, which he formally joined following his return to India in 1940. A widower, Basu is survived by his son, Chandan, who is an industrialist.

— With input from agencies