Trinamool Congress chief Mamata Banerjee showed "political immaturity" in moving a no-trust motion against the UPA-II government with just 19 MPs in her fold, Left Front chairman Biman Bose today said.

"Though she was aware that her no-trust motion will find no taker among other political parties, she went ahead in moving the motion in the Lok Sabha yesterday, which fell through for want of the required numbers," Bose said at a news conference here.

He said since Banerjee had already made public her party's intention to move the no-confidence motion, she had to maintain that stance knowing fully well that it would not get admitted.

"This shows her lack of political maturity. Our party does not function in that manner. We test the waters before hand," he said. Bose said Banerjee had sought CPI(M)'s support for the motion, but the party did not agree because together with the Trinamool, the requisite number would have still been elusive.