Two senior local Trinamool leaders are taking turns to ensure round-the-clock vigil at Sakhawat Memorial school, where the electoral fates of Mamata Banerjee and Suvendu Adhikari in Bhabanipur are sealed.

Sources said Trinamool has organised such vigils outside several strongrooms housing EVMs ahead of Monday’s counting.

Strongrooms are sealed rooms where all EVMs carrying the mandate of the people are stored. The machines will be taken to counting centres on Monday.

In Bhabanipur, the BJP too is sending its workers in turns to Sakhawat to ensure the venue is never left unguarded. However, BJP leaders said they were not maintaining such continuous vigil in most other constituencies.

“Two senior Trinamool leaders in south Calcutta are staying in Sakhawat by turn. One enters around 9pm and stays till morning, after which the other takes over for the day,” said a party leader.

“Our task is to keep our eyes on the live CCTV footage on monitors. We have to watch for any suspicious movement near the strongroom and report it immediately,” another Trinamool leader said.

“Once or twice during the night, we also request central forces to take us to the gate of the strongroom to ensure there is no breach of the seal,” he added.

Chief minister Mamata Banerjee spent nearly four hours at Sakhawat on Thursday evening.

Trinamool has set up two camps at either end of Lord Sinha Road, where Sakhawat is located. Workers stationed at these camps cannot enter the school premises but remain on the road outside.

Trinamool candidates are also keeping vigil outside most strongrooms across the state’s 293 other constituencies.

“They are allowed to ensure that the strongroom gate is sealed and untouched,” said an official from the Election Commission.

In Bhabanipur, the BJP has also created a roster for party workers “on duty” at Sakhawat.

“Someone or the other from the party is present at all times. They are allowed access up to the area where CCTV footage is being monitored,” said Suryaneel Das, chief election agent of BJP’s Bhabanipur candidate Suvendu Adhikari.

Ayan Chakraborty, Trinamool councillor of Ward 28 of the Kolkata Municipal Corporation, posted a picture of himself seated in front of two monitors screening CCTV footage at Khudiram Anushilan Kendra, the strongroom for all seven Assembly constituencies of Calcutta North.

“Someone or the other is always present at Khudiram Anushilan Kendra. We are not leaving the centre without party vigil,” said Chakraborty, chief election agent of Trinamool’s Beleghata candidate Kunal Ghosh.

Ghosh and Trinamool candidate from Jorasanko, Shashi Panja, sat on the road outside the Kendra on Thursday evening, alleging that a BJP polling agent had been allowed entry in their absence.

Panja visited Khudiram Anushilan Kendra again on Saturday.

Sources in the EC said the practice of round-the-clock vigil at strong rooms by political parties is not new. However, they added that the complete lack of trust this time has made the situation more tense.

“It may happen that a CCTV functioning round-the-clock goes off for a minute, or EC officials enter the premises for work. They are suspicious of everything now,” said a district election officer (DEO) with experience in previous elections.

“They are even calling returning officers in the dead of night if they suspect anything,” the DEO added.

An EC official said there is one CCTV camera pointed towards the strongroom door, while two or more cameras usually cover the corridor leading to it. These are considered the most critical feeds.

There is no CCTV inside the strongroom. “There is no live electric connection inside. The mains are switched off to eliminate any chance of a short circuit,” the official said.