Thiruvananthapuram, Sep 1 : Puthuppally constituency in Kerala is set to witness an unusual sight on Friday, when a father-son duo would campaign for rival parties in the run-up to the September 5 bypoll.    While Congress veteran A.K. Antony will hit the campaign trail for Chandy Oommen, his son Anil Antony would seek votes for BJP's Lijin Lal. Taking everybody by surprise, Anil Antony had switched over to the BJP this April and was recently elevated as the party's national spokesperson. Eighty-three-year-old Antony is scheduled to address two public meetings in the constituency, while Anil apart from addressing corner meetings, would indulge ion door-to-door electioneering. Though the main fight in the constituency is between Chandy Oommen and Jaick C.Thomas of the CPI-M, the saffron party's agenda will be on how best they can perform. Notably, the BJP's vote in the constituency surged by over 4,000 votes from the 2016 Assembly polls to reach around 10,000 in the 2021 elections. Oommen Chandy saw his margin of victory come down from 27,092 votes at the 2016 polls to 9,044 votes at the 2021 polls. Hence, the agenda of the father and son would be to see how many votes their respective party's candidates end up with, while A.K. Antony is particularly keen for a resounding victory for the son of his closest aide and friend of more than six decades. Bypoll in Puthuppally constituency was necessitated following the demise of Oomen Chandy --itsMLA since 1970. /IANS