Dinesh Trivedi joined BJP at its headquarters in New Delhi in the presence of party chief JP Nadda.
Railway Minister Piyush Goyal on Wednesday said former TMC MP Dinesh Trivedi tried to do good work during his stint as railway minister, but his efforts were thwarted by West Bengal Chief Minister Mamata Banerjee.
Mr Trivedi served as railway minister from 2011 to 2012.
Mr Goyal said Mr Trivedi must have gauged the defeat of Trinamool Congress (TMC) in the upcoming West Bengal assembly polls before he took the decision to join the BJP.
"Dinesh Trivedi had tried to do good work as railway minister, but Mamataji cut him off. He did not fit her scheme of things. In the history of parliament, find a comparable case wherein someone who has five years and two months left as a Rajya Sabha MP, has quit without thinking about the future.
"Elections are yet to happen and if TMC wins, Mr Trivedi would have lost his seat, and only if BJP wins, he has a chance of getting re-nominated."
"There was no commitment from our side, we did not promise him anything, we did not tell him to resign. Imagine the pain he must have felt to take the decision. He himself said that his conscience did not allow him to continue in an atmosphere of violence," Mr Goyal said.
The railway minister said Mr Trivedi "exposed the TMC's truth in Parliament".
"It was a bold move and it reflects the pain of the people in Bengal. He was pushed to leave. The other aspect is that when he joined the BJP, he must have had the confidence that BJP would win.
"He could have joined the party after the election. But the courage of conviction of the man that he is willing to forgo a five year term. However principled a man is, there is no parallel for this. This clearly shows the winds of change and the momentum for us in Bengal is to be seen to be believed," Mr Goyal added.
Asked to comment on West Bengal CM's allegations of being manhandled in Nandigram, the Union minister claimed that the TMC supremo has lost the plot and is showing signs that her game is over.
Mamata Banerjee alleged on Wednesday that she was attacked by "four-five men" who manhandled her during election campaign in Nandigram, because of which she was injured in the left leg.
The incident happened around 6.15 pm when Banerjee was about to leave Birulia area near Reyapara after praying at a temple.