He has written a second letter to Mr Gadkari, which says, "I am convinced you (Mr Gadkari) are firmly set on the path of suicide and you are determined to drag the whole party with you."
The letter also hit out at Sushma Swaraj and Arun Jaitley for their opposition to the appointment of the new Central Bureau of Investigation (CBI) chief Ranjit Sinha.
Mr Jethmalani dared the party to expel him, saying he was ready for it. "If I am guilty (of making false allegations), they will expel me. I am ready for it," he said at a press briefing in New Delhi today.
"Gadkari's incident (of facing allegations of corruption) has hit the image of the party... they will lose millions of votes... I am not responsible for their lack of wisdom," he said.
The BJP has sent a showcause notice to Mr Jethmalani, asking why he shouldn't be removed from the party. He though claimed that the notice has not reached him yet. "I have read about it in the press. I will reply to it if required, otherwise I will tear it up and throw it in the dustbin," a combative Mr Jethmalani replied.
He also said the deadline set by the BJP for him to respond was not acceptable. "I am a busy lawyer, politician... are they a dictator? I need time till end of December and I will tell Gadkari that," Mr Jethmalani said.
He also dismissed allegations that his attack on the BJP's position on the appointment of the new CBI chief was helping the Congress. "If my position is the same as Congress's, then I am happy. For a change, the Prime Minister has done something good," he said.
Mr Jethmalani also opened a new front against the BJP, attacking the second level of its leadership over the CBI director's appointment. In the second letter, he criticised Sushma Swaraj and Arun Jaitley, leaders of opposition in the Lok Sabha and Rajya Sabha.
The BJP had accused the government of hurrying through the appointment of Ranjit Sinha as CBI director to short-circuit recommendations in the Lokpal Bill that require a collegium to make the choice. The Lokpal Bill is yet to be passed by Parliament.
"Though I am a senior member of the Rajya Sabha and a founder of the BJP, your present leaders either in the Lok Sabha or Rajya Sabha have never once discussed with me anything about the Lokpal bill. I did not know until I learnt from the press that the appointment of the new incumbent was opposed by our leaders on some different grounds," said the second letter written on Monday.
Mr Jaitley today brushed aside Mr Jethmalani's remarks, saying: "I don't think he deserves a reply anymore."
BJP Vice-President Mukhtar Abbas Naqvi said: "I cannot say anything on Ram Jethmalani's letter. I don't give it that much importance."