The Congress on Thursday announced an alliance with Left parties for the West Bengal Assembly election, scheduled for next year.

West Bengal Congress President Adhir Ranjan Chowdhury made the announcement on Twitter. “Today the Congress high command has formally approved the electoral alliance with the Left parties in the impending election of West Bengal,” he said.

Chowdhury had said in September that the Congress and Left parties would unitedly put up a “spirited battle” against the Bharatiya Janata Party and the ruling Trinamool Congress.

However, the BJP ridiculed the idea of a Congress and Left alliance. “Workers of both parties know the Congress-Left deal will not work,” Bengal BJP Chief Dilip Ghosh said. “That’s why they left their parties and joined us last time. It will happen again this time.”

The BJP has also begun holding huge public events in the poll-bound state. Last week, Union Home Minister Amit Shah held a rally in Midnapore district, where rebel Trinamool Congress leader Suvendu Adhikari joined the BJP.

Besides Adhikari, six MLAs of the Trinamool Congress, one each from the Communist Party of India (Marxist), the Communist Party of India and the Congress also joined the BJP. Two-time Trinamool Congress MP Sunil Mondal also switched over to the saffron party.

Also read: West Bengal elections: State Congress chief wants pre-poll alliance with Left Front

At last week’s rally, Shah had said that with the “tsunami of defections”, West Bengal Chief Minister Mamata Banerjee would be left alone by the time elections were held in the state. Banerjee, on the other hand, accused Shah of spreading lies during his visit to Bengal and called the BJP “cheatingbaaz [fraud]”.

The Congress and the Left Front contested the 2016 Assembly elections together. However, of the 294 seats, the Congress won just 44, and the parties constituting the Left Front 32. The Trinamool Congress emerged victorious with 211 seats, and the BJP finished with just three.