Jitin Prasada, former Congress leader and newest BJP recruit, defended his decision and rebutted ex-colleague Kapil Sibal's digs about "Prasada Ram politics" of self-interest over ideology.
"He is a very senior leader (Kapil Sibal). There's no ideology. The only ideology is about national interest. What was the ideology when the Congress aligned with the Shiv Sena? What was the ideology when Congress aligned with the Left in Bengal, and at the same time they were fighting the Left in Kerala," Jitin Prasada said in an interview to NDTV.
"Commenting on a small individual like me won't change the fortune of the Congress."
Earlier on Thursday, Kapil Sibal had denounced Mr Prasada's move to a party he had always opposed.
"We have reached a stage in Indian politics where decisions of this nature are not based on ideology at all. They are based on what I now call 'Prasada Ram politics'. Earlier it was Aaya Ram Gaya Ram," Mr Sibal had told NDTV.
Mr Prasada and Mr Sibal were both among the Congress's "G-23" leaders who had written to Sonia Gandhi last year recommending sweeping reforms including collective leadership. This was considered one of the most standout acts of rebellion in the party against the Gandhi leadership, at least after 1999, when Mr Prasada's father Jitendra Prasada challenged Sonia Gandhi's leadership of the Congress and contested against her for party president.
Mr Prasada appeared to take a swipe at the Gandhis as he said: "The BJP is not in the short-term game of showing individuals in poor light. It is the only national party in real terms. Whoever is inducted is for long term goals."
He also claimed his switch was a long-thought out decision.
"Over the years my role as a politician and helping people was diminishing. I was not able to work for the leader, but today I plan to work for the people whole heartedly," he said.
The BJP is likely to give Mr Prasada, a prominent Brahmin face in UP, a key role ahead of elections in the state next year. The party is hard-pressed to address the resentment of a section of Brahmins who feel their status is diminished compared to the Thakurs; Yogi Adiyanath is a Thakur.
Last Year, Mr Prasada formed an outfit called "Brahmin Chetna", which has made little dent on the ground. The former Union Minister feels he can finally do what he earlier could not, in the Congress.
"I was one of the people involved in the formation of Brahmin Chetna. My aim was to keep it apolitical. We are not deciding where the votes of the community go. It was to address atrocities and problems of the community. I am more in a position to do that with the BJP," he said.