Calcutta, May 7: The Progressive Democratic Alliance to be launched by Subrata Mukherjee at a mass convention at the University Institute hall tomorrow will be headed by a senior Congress leader.

The mayor, who recently left the Trinamul Congress with a view to building ?a mahajot (grand alliance) of anti-CPM forces?, said either defence minister Pranab Mukherjee, Malda MP A.B.A. Ghani Khan Chowdhury or former state Congress chief Somen Mitra will be the organisation’s chairman.

Representatives of the Nationalist Congress Party headed by former MP Bikram Sarkar, the Party for Democratic Socialism led by Saifuddin Chowdhury, the Samajwadi Party and the Janata Party will also attend the convention, besides senior Congress leaders, said Mukherjee. Nationalist Congress Party leaders Tariq Anwar and former Lok Sabha Speaker P.A. Sangma may be present, he said.

?We will elaborate at the convention the reasons for forming an anti-CPM mahajot at this juncture. We will tell the people that our main aim is to prevent a split in anti-CPM votes in the civic polls scheduled for June 19,? Mukherjee said.

?We will seek from the clock symbol for our candidates,? the mayor said, adding that 50 per cent of the seats would be contested by the Congress while the remaining seats would be shared by the other partners of the alliance.

However, Trinamul leaders did not attribute much importance to tomorrow’s convention. ?The so-called Progressive Democratic Alliance will be a replica of the United Progressive Alliance in Delhi,? said Pankaj Banerjee, the leader of Opposition in the Assembly.