BJP turncoat Babul Supriyo retained the Ballygunge Assembly seat for Trinamul with a narrow win on Saturday while another former saffron politician, Shatrughan Sinha, helped Bengal’s ruling party wrest the Asansol Lok Sabha seat from the BJP with a record margin.

CPM candidate Saira Shah Halim came second in the Ballygunge by-election, with BJP nominee Keya Ghosh losing her deposit.

Many saw Trinamul’s sharply reduced margin from the constituency as a “warning” against fielding candidates with pasts like Supriyo.

This and the BJP’s rout in Asansol, which the party had won in 2014 and 2019, prompted a BJP insider to say that “divisive politics has no place in Bengal as yet”.

The outcome of the two by-elections brought relief to the Trinamul Congress at a time probes by the central agencies into a slew of corruption and law-and-order cases in Bengal have left it nervous.

After the results became clear, chief minister Mamata Banerjee visited the Kalighat temple and thanked the voters.

“We are grateful to the people. The love, blessings and good wishes of the people will inspire us to work even better," Mamata said. "Even after all the defamation, propaganda and conspiracy of the BJP, CPM and the Congress, people have reposed faith in us…. The people of Bengal and India know that the Trinamul Congress is their biggest hope in all seasons."

For Mamata's party, the biggest takeaway is the BJP's defeat in the heart of Calcutta and in Asansol - along with the message that the anti-Trinamul vote remains divided.

In Ballygunge, the BJP won just 12.83 per cent of the votes against Trinamul's 49.69 per cent while in Asansol, Trinamul (56.6 per cent) polled nearly twice as many votes as the BJP (30.5 per cent).

"The Left got the second spot in Ballygunge with over 30 per cent votes while the BJP secured the second spot in Asansol with around 31 per cent votes," political scientist Biswanath Chakraborty said. "This means, anti-Trinamul voters are confused whom to vote for and this is the best news for the ruling party in Bengal."

Mamata at the Kalighat temple in Calcutta on Saturday. The Telegraph

However, the Ballygunge verdict contained a caution for Trinamul, with its victory margin whittled to just over 20,000 from Subrata Mukherjee's 75,000-plus margin less than a year ago.

In its official reaction, Trinamul attributed the thinner margin to a lower voter turnout -- 42 per cent in the by-election against more than 61 per cent last May. But this did not explain the plunge in the ruling party's vote share from 71 per cent last year to 49.6 per cent this time.

In off-the-record conversations, several Trinamul leaders admitted that the fall in vote share -- a rarity since their party came to power in 2011 - owed solely to Supriyo's candidature. During his days in the BJP, Supriyo had been known for making divisive and inflammatory comments.

Ballygunge, a constituency with over 42 per cent Muslim votes, had witnessed a "No vote to Babul" campaign in the run-up to the by-election.

"We had to face uncomfortable questions from the voters, who showed us clips of Babul's derogatory comments against Muslims who had taken part in the anti-NRC and anti-CAA movements," a Trinamul insider said. “The voters, especially Muslim voters, have given us a warning that while they are very much with us, they will not support candidates like Babul."

This seems the main reason behind the spike in the CPM's vote share to 30.06 per cent. In 2021, the candidate for the Sanjukta Morcha (an alliance of the Left, Congress and ISF), who happened to be Saira's husband, had received only 6 per cent of the votes.

The "phenomenal" improvement in vote share prompted the CPM state leadership to claim that a silent reversal in voter preference in Bengal had turned the Left into the most credible alternative to Trinamul.

"The people of Ballygunge have given a clear verdict that the BJP is a fake Opposition.... The phenomenal increase in the Left's vote share within a year is a record not only in Bengal but across the nation," CPM state secretary Md Salim said.

Some within the party, however, are continuing to ask why the CPM's tallest leaders - such as Sitaram Yechury and Brinda Karat - hadn't come to campaign for Saira, who fought primarily on her own steam.

The CPM's social media ecosystem, however, was quick to highlight that Saira had won from Wards 64 and 65 of the Calcutta Municipal Corporation, holding this up as proof of the Left's elevation to the status of main Opposition.

Chakraborty, the political scientist, cautioned the CPM against going overboard with the Ballygunge result.

"I think the spike is primarily because of the mood against Babul.... I should also mention that the CPM lacked the sort of organisational presence in the area that could have provided Saira with an edge," he said.

"Instead, fledgling forums like the one against the NRC, led by Left economist Prasenjit Bose, played a much more effective role, successfully rolling out the 'No vote to Babul' campaign."

Chakraborty added: "Had it been a different candidate from Trinamul, the vote share would have been different too. So, the Left should realise it has a long way to go before it can claim to be the main Opposition."

Ballygunge also had a message for the BJP, shocked at Ghosh forfeiting her deposit after a campaign replete with tall claims.

"Not only did we lag in organisational might, we didn't have a proper narrative, either. It's also true that divisive politics has no place in Bengal as yet," a BJP insider said.