The state government has decided to adopt Poila Baisakh, which marks the start of the Bengali lunar calendar, as West Bengal Day.

Sources said during the ongoing monsoon session of the Assembly, set to resume on Tuesday, Trinamul MLAs would bring a resolution before the House in this regard.

According to Trinamul sources, the decision has the backing of chief minister Mamata Banerjee as it was her idea to come up with a date to counter the saffron camp's bid to establish June 20 as the state's foundation day. The Bengal Assembly on June 20, 1947, passed a resolution to divide the Bengal province.

"I suggested a date keeping in mind the composite culture of the state, the ideals of Rabindranath Tagore and Subhas Chandra Bose, and their idea of Bengal," said historian Sugata Bose heading a committee formed to identify the day to celebrate the state.

He refused to confirm if the day he suggested was Poila Baisakh but said it was selected from a few options.

He said the reason for this exercise was to "extricate" the state from the divisive tendencies evoked by June 20.

Apart from Bose, the committee includes ministers Firhad Hakim, Sobhandeb Chattopadhyay and Bratya Basu.

On Monday, Bose handed over a note regarding the decision to Speaker Biman Banerjee. It will be used as a referral note to prepare the resolution, sources said.

Bose also suggested an anthem for Bengal.

"My suggestion was to adopt a song by Rabindranath Tagore written in 1905 as an anti-Partition song, as the anthem of our state," Bose said, refusing to divulge it.

These suggestions have apparently been accepted by the Speaker.

Earlier this year, when Raj Bhavan announced it would observe June 20, a "stunned and shocked" Mamata wrote to governor C.V. Ananda Bose requesting him not to. But he did, earning plaudits from state BJP leaders. Raj Bhavan later said it had acted on the Centre's "advisory".

The resolution to adopt the inclusive Poila Baisakh as Bangla Diwas will counter the divisive BJP agenda, Trinamul sources said.

"Poila Baisakh has cultural significance. All Bengalis, irrespective of caste, creed and religion, celebrate it," a Trinamul leader said.

Reacting to this, BJP state chief spokesman Samik Bhattacharya said Trinamul wanted to "woo Muslim votes" and "were planning to suppress the bloody history of the Partition".