Governor A S Gavai accepted the resignation and asked Achuthanandan to continue as Chief Minister till the new ministry is formed by UDF, which secured 72 seats in the 140-member house.
Speaking to reporters later, the 87-year-old Marxist veteran, who spearheaded the Left Democratic Front''s campaign, said the party accepted the people''s verdict and would not indulge in any undemocratic means to remain in power.
"People have given their verdict. We will not do anything undemocratic to undermine that. When we get a chance to seek a mandate, we will compete and try to return", he told reporters after handing over the resignation.
Achuthanandan, however, indicated he would not be lenient towards the UDF government if corrupt, morally suspect and those with criminal background are given cabinet berths.
Asked about the chances of his being taken back to the CPI(M) politburo in view of his vital role in the LDF campaign, he said it was for the party to decide on such matters and he did not intend to intervene.
He termed the drubbing received by the Left Front in West Bengal as a temporary setback from which the coalition would soon recover and recalled that in 1970s, the state was ruled by the Congress under Siddharth Shankar Ray but the Left had returned to power in 1977 under Jyoti Basu.