A university professor got a lesson in 'rigpolitik' from a former student at a polling booth in New Barrackpore on Monday.

Mathematics teacher Priti Kumar Roy, 43, of Jadavpur University was the polling agent of the CPM candidate in a booth in Dum Dum North constituency and his former student an agent of the Trinamul Congress candidate.

Roy's student had asked him to leave the polling booth 30 minutes before the end of the voting hour, saying there were instructions from the ruling party's leaders to "conduct voting". He refused.

Hours after the snub, a group of suspected Trinamul supporters landed up in front of the Jadavpur University teacher's home, hurled stones at the two-storey house and threatened to teach him a lesson after May 19, when the election results are due.

In Birati, about 4km from the booth where Roy had resisted rigging, CPM candidate Tanmoy Bhattacharya's car was attacked. A stone smashed the rear windscreen of his car and some shards of glass cut his arm.

Roy recounted his plight to Metro on Tuesday, starting with a former student trying to shunt him out of the polling booth and culminating in the attack on his home.

Around 30 minutes before the end of voting, the polling agent for Trinamul, Tanmoy Sikdar, who was once my student, came to my desk and said: "Sir, apni ektu baire chole jaben kichukhhoner jonno (Sir, please step outside the booth for some time)."

I was shocked. Here was a boy I had once tutored at home.

He was polite but sounded desperate. I asked him why he wanted me to step out and he said: "There is pressure from leaders... Amader vote kortey hobey sab shesh hoye jabar aagey (We have to conduct voting before the close)."

I told Tanmoy there was no question of me leaving the booth. He had been my student in the mid-Nineties and we have known each other for a long time. He has been respectful towards me whenever we meet.

When I turned down his offer, Tanmoy returned to his seat. I left Booth No. 7 at the New Barrackpore Boy's High School after polling was over and the EVM was sealed.

I reside in Ward 7 (of New Barrackpore Municipality), which has around 7,000 voters. Around midnight on Monday, I heard people shouting in front of my house. My brother, who is an assistant manager with the state electricity board, resides on the ground floor. He immediately came up on hearing the commotion.

I knew that the attack was the fallout of my refusal to accept my former student's request inside the polling booth.

The attackers tried to break the lock on one of the gates but couldn't. They targeted the second gate and again failed. They then hurled stones at the house.

The threats that followed confirmed who they were. Before leaving, the Trinamul mob declared that I would be taught a lesson after the poll results are declared on May 19.