Ahead of the crucial Chengannur bye-election, the ruling CPI-M, which is fighting to retain the seat, on Tuesday got a shot in the arm when former Congress leader Sobhana George, who represented the constituency from 1991 to 2005, joined the party

The bye-election became a necessity following the sudden demise of sitting Communist Party of India-Marxist legislator KK Ramachandran Nair in January this year.

Even though the date of the bye-election is yet to be announced, all the three rival fronts have begun campaigning, with Chief Minister Pinarayi Vijayan launching the Left Democratic Front's campaign with a meeting on Tuesday evening, where George was sitting on the dais with top Left leaders.

A few days back, CPI-M State Secretary Kodiyeri Balakrishnan along with party candidate Saji Cherian called on George and requested her support, to which she readily agreed.

During the 2016 assembly polls, George, who failed to get a Congress ticket, contested as a rebel candidate in Chengannur and secured 3,966 votes, which was partly responsible for the defeat of Congress legislator PC Vishnunath, who was aiming for a hat trick of victories.

Till Monday, the Congress was hopeful that George will return to the party and had offered her a seat in the party executive, but with the CPI-M's wooing proved to be more effective.

The Congress candidate is D Vijayakumar, a front line leader who has always worked for the party in Chengannur, while former state BJP president PS Sreedharan Pillai, who finished a close third in the 2016 polls, has already started his campaign.

The Congress party is launching their campaign on Thursday, while the BJP is still sorting out its difference of opinion with the newly-formed BDJS, the second biggest ally of the BJP-led NDA in the state.