Only a united Communist movement, which could emerge as a third front, could combat the challenges posed by communal forces, CPI sources here said.

The unification issue, the sources said, was discussed threadbare at every district party conference, where it was pointed out that the percentage of votes polled separately by the two parties in the Lok Sabha was lower as compared to the percentage of votes polled when the party was united.

At Calcutta, Karar today severed his 55 year association with the party alleging ``injustice'' and ``growing infighting'' in the party.

The veteran labour leader told newsmen that his ``serious allegations'' against the leadership did not find favour with the national council. ``It isamazing that the national council remains indifferent to the rampant corruption in the state leadership.''

Party insiders, however, said Karar had remained ``aloof'' from the party's day to day functioning for several years and his allegations were ``unfounded.''

Senior CPI leaders, including the State Minister for Water Resources and Agro-Industries Corporation, Nandagopal Bhattacharya, Manju Kumar Majumdar and others would be present at the four-day state conference.