With no role left in forming the government at the centre, the Left, which once used to dictate terms to the Manmohan Singh-led UPA government as an alliance supporter, is now reconciled to sitting in the opposition.

CPI (M) leader Prakash Karat today accepted defeat and said his party would now sit in the opposition. "We will sit in the opposition," said Karat.

"No denial that the Congress has won. We will continue to sit in the opposition, as we always have," Communist Party of India (CPI) general secretary AB Bardhan said while conceding defeat.

The Left parties fared badly in its stronghold in West Bengal and Kerala, conceding seats to Congress party-led coalition government for four years before falling out over a nuclear deal with the United States.

Karat also acknowledged that the election result was a rejection of the Left's ideological stance and that it was a "major setback" for the Left.

Clearly, people had voted "on the basis of the platform put forward" by the Congress and its allies, he said.

He said the CPI (M) politburo and the central committee meetings on May 18-19 would discuss the Left parties' dismal performance in Kerala and West Bengal.

Karat also faced criticism from his own partymen for the kind of policies the CPI (M) followed.

"It is the tragedy of a sectarian political line," said senior CPI leader CK Chandrappan. "An overall review of its policies is needed," he added.

Chandrappan also lamented the fact that the Left, which contributed a lot to the UPA government's pro-people programmes like National Rural Employment Guarantee Act (NREGA), had to withdrew support to the UPA government for adopting imperialist policies, a subject that the people are not much concerned about.

The Left had withdrawn its support to the UPA government over its nuclear deal with the United States.