The large-scale defection of municipal councillors and some legislators on Tuesday from the Trinamool Congress to the BJP may only be a trailer of the big picture that could unfold in West Bengal in the coming months, with state opposition leaders calling it the beginning of the end of the Mamata Banerjee-led outfit.

Two Trinamool MLAs — BJP leader Mukul Roy's son Subhrangshu Roy and Tushar Kanti Bhattacharya, the latter still officially a Congress legislator despite having ditched the party to join the Trinamool in 2016 — one CPI-M legislator Debendra Nath Roy and over 50 councillors of three municipalities joined the saffron outfit in Delhi during the day.

The immediate impact of the desertions is the Trinamool has lost control of the boards in Halishahar, Naihati and Kanchrapara municipalities in North 24 Parganas district. Halishahar and Kanchrapara are part of the Bijpur assembly segment, represented by Subhranghsu Roy. Naihati is a separate Assembly constituency.

All three municipalities are part of the Barrackpore Lok Sabha seat, from where another defector from Trinamool to BJP, Arjun Singh, emerged victorious in the recent elections.

Bahubali leader Singh, a four-time Trinamool legislator from Bhatpara, in fact added to his former party's misery during the day, as he organised the defection of eight Trinamool councillors of Bhatpara municipality to the BJP.

The BJP, which now has 19 councillors in the 35-member municipality, is now set to capture the board.

That makes it the loss of four municipalities on a single day, the second biggest shocker for Mamata Banerjee after the Lok Sabha election setback.

But what could have further raised the blood pressure of Trinamool leaders is BJP leader Mukul Roy's comment that within the next two-three months, his party would take over 55-60 municipalities in the state.

Coming from once considered an expert in engineering defections, the remarks could be an indicator of how the political scene could unravel in the coming days.

Besides the two MLAs who joined on Tuesday, the names of a lot of Trinamool legislators are floating around as potential BJP recruits. Among them are Sabyasachi Dutta, Siuli Saha, Shilbhadra Dutta, Gautam Das and Sunil Singh. While the two Duttas and Saha are considered Mukul Roy loyalists, Singh is a relative of the new Barrackpore MP.

Speaking off the record, Trinamool leaders express apprehensions of a deluge of defections from their ranks in the coming days.

In fact, senior minister and Kolkata mayor Firhad Hakim inadvertently described the deep crisis the Trinamool faces when he likened his party to a "ship rocked in the face of a storm" while comparing the deserters to "rats".

"When a ship is rocked in the face of a storm, the rats jump into the sea without knowing their fate. The same is happening now. We are sure, those who are joining (BJP) are being forced to do so," he said.

But Congress Rajya Sabha member Pradip Bhattacharya and CPI-M state secretariat member Shyamal Chakraborty were not ready to shed tears for Trinamool.

Bhattacharya recalled the way the Trinamool had poached MLAs, municipal councillors, panchayat functionaries from CPI-M and the Congress in the past to take control of elected bodies.

"They are being paid back in their own coin. The Trinamool had started its journey and consolidated itself by breaking the Congress. Now it has started coming apart. And that is natural," Bhattacharya told IANS.

"Trinamool will collapse fast," Chakraborty told IANS.

However, state Congress vice president Om Prakash Mishra had a different take.

"BJP's expansionism could not only be socially divisive and politically destabilising, it would also have negative consequences for the state. I condemn the forced and dangerous expansionism of BJP facilitated by the employment of ill-gotten wealth of the BJP leadership," he told IANS.