The issue was missing from the party's campaigns for the first four phases and political observers believe that raising it then could have proved counterproductive for Trinamool.

This is because out of the 18 Lok Sabha constituencies where voting took place, three candidates of the ruling party do not have their roots in West Bengal.

The first two former Indian cricket team players are Yusuf Pathan from Baharampur constituency in Murshidabad district and Kirti Azad from Bardhaman-Durgapur West Burdwan district.

The third candidate is yesteryear's popular star Shatrughan Sinha, who contested from Asansol in West Burdwan district.

While Azad and Sinha have their roots in the neighboring state of Bihar, Pathan is from Gujarat.

While Sinha has been able to establish a connect with Asansol over the years after being elected in the by-election in 2022, Pathan and Aja are connected to their constituencies just ahead of the elections this year.

Now, with polling over for Asansol, Bardhaman-Durgapur, Baharampur and Darjeelin, Trinamool is aggressively raising the external issue in its campaigns.

This is evident from the frequent references to the "cultural and food Habi invasion" during campaigning by ruling party leaders.

Even Chief Minister Mamata Banerjee drew attention to some north Indian states and expressed fear of banning non-vegetarian food in West Bengal if the BJP comes to power.

Political observers say the "outsider" issue affected voter sentiments in the 2021 West Bengal Assembly elections, especially in the state capital Kolkata and its surrounding districts, and Trinamool made huge electoral gains from it.

Therefore, political observers predict that the ruling party will adopt a more aggressive stance on this in the remaining three phases.