The “informal” alliance among the Left and Congress for the Siliguri Municipal Corporation, scheduled on February 12, took a new turn on Sunday as veteran CPM leader Asok Bhattacharya, along with some other party leaders, campaigned for Congress candidate Sujay Ghatak of the city’s ward 16.

In Siliguri, ward 16 is one of the four seats where the Left has not fielded any candidate. The Congress, on the other hand, has abstained from pitting its candidates in 13 seats which the Left had won in the last civic polls in 2015.

“The understanding (between the Left and the Congress) was informal so far but this time, it became somewhat formal as the Darjeeling district Left Front circulated a leaflet in ward 16 and in another ward, seeking support for the Congress candidate. But what the residents witnessed today was a rare scene. Left leaders like Asok Bhattacharya and Jibesh Sarkar campaigned for Sujay Ghatak, which has hardly ever happened in the civic polls here,” said a political observer.

Bhattacharya, when questioned on the issue, said they were backing the Congress candidates to thwart Trinamul and the BJP from securing a majority in the 47-ward SMC.

“It is true that there has been no formal alliance with Congress ahead of the civic elections but one can never rule out a post-poll alliance. We want the Left and other secular parties to form the board here,” said the former mayor of Siliguri.

Shankar Malakar, the Darjeeling district Congress president, thanked the Left.

“We welcome their decision to campaign for our candidates. If required, we are ready to campaign for the Left candidates in those 13 wards where we have not put our candidates,” he said.

The “Siliguri model" or tacit understanding among the Left and the Congress was known since 2009 when the Left had supported the mayoral candidate fielded by the Congress to stop Trinamul from winning.

It is this same understanding that helped the Left, which came to power in the SMC in 2015, to run the civic body despite not having a majority.

The Left had lost majority within a few months after coming to power and Congress councillors refrained from tabling a no-confidence against them, despite sitting in opposition with Trinamul and the BJP.