Kolkata: For at least two years, Mukul Roy, a co-founder of the Trinamool Congress (TMC), has been straining at the leash to join the Bharatiya Janata Party (BJP). When he finally did so last week, it was made clear by the leadership that he was admitted to the BJP at his own request.

On Friday, Union minister Ravi Shankar Prasad said Roy was joining the BJP “unconditionally" as party president Amit Shah conspicuously stayed away from the media briefing. His role in the party is not defined yet but BJP leaders in Delhi and Kolkata have said the party expects to gain from Roy’s understanding of electoral politics in West Bengal.

With panchayat, or village council, elections approaching next year, Roy, 63, may have only a few months to prove his worth and cement his position in the BJP.

As federal agencies such as the Central Bureau of Investigation (CBI) and the Enforcement Directorate (ED) turned up the heat against TMC leaders for allegedly helping the now defunct Saradha Group ply its illegitimate deposit collection business, Roy in 2015 started to distance himself from the party.

At that time, the BJP’s leadership in Delhi wasn’t keen to engineer a rift within the TMC by fielding Roy, said one of his close aides, asking not to be identified. But now the BJP is determined to “uproot" the TMC from West Bengal, and Shah made that clear to workers during his last visit to Kolkata September this year, this person added.

Roy is embroiled in another controversy. Seen in a controversial Narada News sting operation, he is one of the leaders being investigated by the CBI and the ED. Narada News conducted a sting operation and released footage showing several TMC leaders receiving cash from the representative of a fictitious firm. The sting operation was conducted in 2014 but the footage was released ahead of the 2016 assembly election.

TMC secretary general Partha Chatterjee said that Roy defected under pressure from the federal agencies and that for some time he had been trying to undermine the party from within.

On Friday, while addressing the media, Roy had said the BJP isn’t a communal party and that the TMC had previously benefitted from being one of its allies.

Addressing the media on Monday, Roy said the change that people had voted for in 2011 did not materialize, adding that those who still want change must back the BJP.

The BJP has realized that its campaign against TMC leaders over corruption is not winning votes, said Biswanath Chakraborty, a professor of political science at Kolkata’s Rabindra Bharati University and an independent election analyst. Because it doesn’t have anyone better to deal with elections, the BJP was “forced" to go with Roy, he added.

Dilip Ghosh, BJP’s state president in West Bengal, on Saturday said he will continue to call the shots and that he, on his own strength, will get more people from the TMC to join the party, adding that Roy will add to the party’s organizational strength.

“Roy is up against a huge challenge," said another BJP leader, who asked not to be named. The task is cut out for him: there are dissidents within the TMC, and Roy’s job is to convince them that the BJP is not “untouchable", this person said.

It is expected that Roy will spread the same message across West Bengal’s 77,000 polling booths and work at the grassroots level to expand the BJP’s support base, said the BJP leader cited earlier.