By Suvojit Bagchi
BBC News, Calcutta
Ms Banerjee has not been seen on so many posters for years
Thousands of billboards and posters of West Bengal's opposition leader, Mamata Banerjee, line the streets of Calcutta.
The poster blitzkrieg by the Trinamool Congress (TMC) and its leader could represent the waning powers of West Bengal's leftist government - the longest serving democratically-elected communist government in the world.
Many Calcuttans feel that this flood of pro-Banerjee billboards in the "homeland" of the Indian communists is a sign of her increased popularity, particularly given that in India the volume of publicity during elections is a sign of a party's mass base.
"TMC's banners have made it evident that the left coalition has been challenged after a long time," said taxi driver Prashanto Patra.
However long-time member of the ruling Communist Party of India (CPI-M), Anindya Ghosh Dastidar, has another view: "Backed by imperialist forces, Banerjee could spend for billboards."
But few in the know would deny that Mamata Banerjee is the biggest electoral challenge to the leftist government led by the CPI-M.
Exactly three years ago, Mamata Banerjee and her party seemed to be a spent political force.
In 2006, the TMC won 10% of the seats in a local assembly election, while the left coalition won nearly 80% of the seats. In national elections in 2004, the TMC won only one of the 42 seats of West Bengal state.
At that point she was considered something of a "political oddball".
The left's successive electoral victories since 1977 can largely be attributed to its policy of partial distribution of farm land among small and marginal farmers. In urban Bengal, the left's inroads into workers', students', women's and intellectuals' collectives have made it virtually impossible for opposition parties to penetrate the CPI-M's vote base.
"The CPI-M's control over mass organisations and civil society groups were so well orchestrated that any dissent is always nipped in the bud," says political scientist, Sanjib Mukherjee.
But signs of the left's waning popularity began to surface in the 2006 local assembly elections.
"The opposition parties got 49.8% of the votes, but only 20% of the seats, whereas the left coalition got 50% of the votes and 80% of the seats," says Debabrata Bandopadhyay, one of the main architects of the land distributions policy and now a major ideologue for the TMC.
He explains Mr Banerjee's rise as a product of an alliance between the main opposition parties in Bengal - the Indian National Congress (INC) and the TMC. "The split in the anti-left vote helped the ruling left," he says.
Campaigning ends on Monday in West Bengal
The other reason for Mamata Banerjee's comeback has been attributed to the West Bengal government's initiative to acquire vast tracts of agricultural land in Singur and Nandigram in south Bengal for the car and chemicals industries respectively.
Both projects were withdrawn in the face of resistance from local farmers as well as from urban elites.
More than 30 people died in the protracted battle between farmers and state-led security forces, denting the image of the CPI-M-led coalition.
It was into this void that Ms Banerjee stepped.
Taking up the issues of small farmers, Ms Banerjee, who was earlier aligned with right-wing Bharatiya Janta Party (BJP), became a cheerleader of Bengal's rural poor.
"A fantastic political merry-go-round took place in Bengal," says Biplab Chakravarty, a political activist and publisher.
Ms Banerjee realised that revolutionary action works wonders with the poor.
"She resorted to Marxist rhetoric, whereas Marxist parties changed their class position and started acquiring farmers' land for private investors," says Mr Chakravarty.
The result is the TMC's election manifesto which states, among other things, that creating economic zones for industry violates labour laws and is "unacceptable".
This change in political philosophy has helped Mamata Banerjee to stage her comeback.
For a long time Mamata Banerjee's lower-class origins worked against her among urban middle class voters.
"She sounded politically naïve, could not speak in English and did not have an intellectual schooling - the Bengali hoi poloi rejected her," said Mr Chakravarty.
Added to that was Ms Banerjee's image as a demagogue.
Nevertheless, following the land movements, the TMC won the support of a section of the Bengali middle class alongside its rural poor. Some Bengali intellectuals feel that the pressure of leading a people's movement has "matured Banerjee".
Ms Banerjee then started talking coherently about her political plans, says writer-activist Joya Mitra,
"Her associates were singing those protest songs which the left used to sing 30 years ago to dislodge the landed gentry.
"Moreover, her guts to take her mighty opposition head-on, regardless of the fact that she was attacked several times, boosted Banerjee's image substantially," says Joya Mitra.
But her metamorphosis has not impressed all.
Shibaji Bandopadhyay, director of Calcutta's premier social science institute, points out, that Ms Banerjee was with a right-wing party "even recently".
"People are sick of the CPI-M's authoritarianism, so a vote for the TMC is an anti-CPI-M mandate, rather than a pro-Banerjee one," says Professor Bandopadhyay.
West Bengal's communists, however, are not perturbed by Mamata Banerjee's growing popularity.
Sitting in the CPI-M party headquarters, politburo member Shyamal Chakravarty told the BBC that the party's strength would "neither increase nor decrease" in the election.
He also refused to accept that the alliance between Congress and the TMC would create any problems.
"They aligned in 2001 and we had a thumping victory," he says. Biplab Chakravarty also refused to accept the left coalition is on the defensive because of the setback in land movements.
But one thing is clear - the Banerjee-led opposition has seriously challenged the leftist hegemony in West Bengal for the first time in 32 years.