Jan. 31: Only four months to go for elections to 18 civic bodies, including Calcutta Municipal Corporation, Mamata Banerjee?s Trinamul lost control over a municipality it held as 10 of its councillors defected to the Congress.

The party today took control of Bolpur municipality and signalled similar developments in civic bodies run by Trinamul.

The Trinamul councillors, led by former party MLA from Bolpur Sushovan Bandopadhyay, switched allegiance this afternoon in the presence of Pranab Mukherjee. The state Congress president was in the Birbhum town along with MP Adhir Chowdhury to address a rally.

After the mass defection, Trinamul is left with six councillors in the 18-member municipal board. The Congress has 10 and the CPM two.

?It is a major victory for us? The Congress is emerging as a force to reckon with in Bengal. We are optimistic that Trinamul councillors in other municipalities also will return to our party in the next few months,? said Nihar Dutta, the district Congress chief.

A Birbhum Congress functionary predicted the same fate for the Trinamul-controlled Suri municipality. ?In the 18-member board there, we have increased our strength to seven. A Trinamul councillor is now with us. Six more should take cue from their Bolpur counterparts.?

Nibir Banerjee, Trinamul?s Birbhum vice-president, said the defectors ?betrayed the 70,000 people of Bolpur?. He added: ?They won the 2002 municipal polls with the Trinamul banner, it is unfair on their part to switch over to the Congress.?

Trinamul lost control over Hooghly-Chinsurah, Rishra and Bansberia municipalities in Hooghly last year. In all the cases, its councillors moved to the Congress. Pankaj Banerjee, the leader of the Opposition in the Assembly and a key Trinamul functionary, admitted in Calcutta that the Bolpur development would cast a shadow on the civic elections in June. ?We have called for explanations from those who have joined the Congress. Mamata has also been briefed,? he said.

The Trinamul leader also criticised Mukherjee for ?engineering the split?. He said: ?It does not befit Mukherjee, the defence minister, to woo our members.?