All 48 police stations in the city have been asked to scan the lanes and bylanes leading to the route of the chief minister’s convoy and both flanks of the roads on which he travels.

The directive, from officers responsible for Buddhadeb Bhattacharjee’s security to the heads of all police stations, states that the VVIP’s “path of travel” and all adjacent roads and lanes should be “sanitised” before the convoy passes.

“Earlier, only the flank through which the convoy passed used to be scanned. Now the other flank, too, will be screened,” said an officer.

The authorities have also decided that the special unit which looks after the chief minister’s security will always be accompanied by officers from anti-sabotage checking units, a protocol not usually followed.

Senior officers said the directive had to be issued as Bhattacharjee, unlike L.K. Advani and Narendra Modi who strictly adhered to security norms, often broke protocol to mingle with the people.

The decision to scan the lanes and bylanes follows the November 2 blast in Salboni, where a remote-controlled blast struck a police jeep in a convoy carrying Union steel minister Ram Vilas Paswan and his deputy Jitin Prasada, leaving six injured.

The blast, at a spot 150km from the city, exposed a serious security lapse — the cops had focused only on the VVIP route ignoring the adjoining areas, including the paddy fields.

“In Salboni, the paddy fields provided cover to the wire that triggered the blast. In the city, it could be anything on a VVIP’s route. We don’t want to take chances. The usual practice in the city is to scan only the main path of travel, but now we are focusing on the adjacent lanes and bylanes, too,” said a senior officer in Bhattacharjee’s security team.

The directive states that if required, Bhattacharjee should be persuaded to change his route at regular intervals, as is done with all those in the Z-plus security category.

The chief minister, sources said, is not too keen on frequent route changes during his daily trips from the Palm Avenue residence to the CPM headquarters on Alimuddin Street, and from there to Writers’ Buildings. While returning home, he usually drops in at Nandan.

The directive also highlights the need for better coordination among the anti-sabotage checking units, intelligence units and the special security unit.

Officers said a special arrangement had been put in place for a programme on November 7 at Esplanade, where Bhattacharjee and other senior Left Front leaders would pay tribute to Lenin.

While preparing the directive, the officers had taken into account information provided by various agencies tracking Maoist operations across the state.

The inputs suggest that though the Maoists are yet to raise an “action squad” in the city, some members of its Calcutta committee have been trained in the use of arms in the Saranda forest in Jharkhand. “A report prepared by the central committee of the CPI (Maoist) has spoken of a strategic retaliation against security forces,” said an officer. “If you read between the lines, the signal is loud and clear.”