Security around West Bengal chief minister Mamata Banerjee’s Kalighat residence was beefed up, a day after a section of para-teachers waded into the waters of Tolly Nullah only 100 metres from the TMC supremo’s house to demand for a salary hike, a senior police officer said.

Police pickets have been posted in at least seven locations.

A boat has been deployed to keep a round the clock surveillance . Personnel of DMG (disaster management group) have been deployed there to avert any chance of misadventure. Vigil from watchtowers from the Alipore Central jail has also been increased, an officer at Lalbazar said.

The number of policemen regularly posted in the vicinity of the chief minister’s house has also been increased.

The attempt by the parateachers exposed the chinks in the security arrangement in and around the chief minister’s residence at Harish Chatterjee Street.

The sensitivity of the incident had forced the commissioner of city police Soumen Mitra and other senior officers to rush to the spot. Six men and a woman were arrested from the spot.

Dilip Ghosh, president of the BJP state unit snapped at the state government for reducing the para-teachers to a point of such a low that they were being forced to wade through cananl water to see their demands were addressed.

Contractual teachers have been holding a sit-in in the metropolis for more than 70 days, demanding immediate wage revision.