The party claimed that BJP withdrew its candidate at last moment in favour of Banerjee's party.
"This is BJP's gift to Mamata for walking out of UPA. BJP withdrew its candidate at the last moment from the seat in favour of Banerjee's party. Had the BJP candidate contested the poll, her candidate would not have won," said the AICC in-charge for West Bengal Shakeel Ahmed.
"When a party does not field a candidate in elections and issues appeals not to vote against some particular parties barring one, it means the party is supporting a particular party," he said.
In the lone Lok Sabha bypoll in Howrah in West Bengal, the ruling TMC retained the seat with a margin of over 27,000 votes defeating the nearest CPI(M) rival. Congress settled at the third spot.
Congress candidate Sanatan Mukherjee was polled 96,727 votes. The seat had fell vacant following the death of TMC MP Ambika Banerjee.