Expressing doubts over the Congress' seriousness to fight the Communist Party of India (Marxist) in West Bengal, Trinamool Congress chief Mamata Banerjee has cold-shouldered the party's proposal of forming a secular democratic platform to fight the Marxists.

"We had to leave Congress because the party always surrendered to CPI-M. Congress has not changed this policy," she said, reacting to the overtures made by the state Congress leadership on Saturday.

Seeking an anti-left alliance comprising Congress and TC, former PCC president Somen Mitra had stated it was the need of the hour for an alternative to Left Front rule.

"The results of the last assembly elections have proved that Congress cannot alone unseat the Left Front from power," Mitra, who belongs to Pranab Mukherjee's camp said.

Though the Congress high command has insisted that there could be no truck with TC as long as she remained in the NDA, PCC leadership argued that Mamata was maintaining a distance from BJP and moreover there is no NDA in West Bengal.

TC insiders said at the moment she was not willing to join hands with any faction of state Congress and was more interested in strengthening her party organisation before next year's panchayet election in the state riding on the people's sentiment on Nandigram. 

The Trinamool leader has also not spared the Congress high command, charging them with remaining an 'onlooker' after the killing of innocent people at Nandigram.

Congress was behaving like a 'seasonal bird', and 'betraying' the agitation against land acquisition, she told a meeting of TC's minority cell on Sunday.

She had also said that Prime Minister Manmohan Singh had not cared to visit her during hunger strike in December despite being in the city.

Frustrated with UPA government's cold response to her demand for intervention after the Nandigram incident, the TC supremo said that the Congress-led government remained an 'onlooker' because it was taking the CPI-M's support.

After the police firing at Nandigram she had repeatedly demanded central intervention saying that it was the constitutional obligation of the Centre to intervene when women, children and minorities were tortured and killed at Nandigram.

The TC chief also distanced her party from BJP in its fight against the land acquisition at Singur despite being a partner of the NDA at the national level primarility with an eye to get the minority support.