Intensifying his fight against elder brother Mukesh, Anil Ambani on Monday resigned as vice chairman and director of Reliance group company Indian Petro Chemicals Ltd, accusing another director Anand Jain of heading a 'conspiracy to divide' the brothers and play a 'negative role' in their family affairs.

"I consider against my dignity, self-respect and self-esteem to be on the same board as Anand Jain," Anil said in his resignation letter to IPCL [Get Quote] Chairman Mukesh.

Younger Ambani, who declared a war against Mukesh by questioning the motives behind the buyback proposal barely minutes before flagship company RIL's [Get Quote] board meeting on December 27, said in his letter: "Anand Jain is heading the conspiracy to divide us (brothers) and to further worsen our differences."

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RIL officials confirmed the receipt of the resignation by Mukesh Ambani, IPCL Chairman.

Anand Jain, who considered close to Mukesh and is vice chairman of Reliance Capital [Get Quote], refused to comment on the issues raised by Anil.

An RIL spokesperson said that the flagship company, headed by founder chairman Dhirubhai Ambani, had nominated five directors -- Kamal Nanavati, Nikhil Meswani, Anand Jain, S K Anand and K G Ramanathan -- and Mukesh Ambani as chairman after acquiring the erstwhile public sector petrochemical unit.

Clarifying that Anil was not nominated to the board of IPCL at the time of acquisition, the spokesperson said that he was taken in as a director in place of K G Ramanathan on Mukesh's proposal and was made vice chairman after his father's death by IPCL chairman.

Anil, who was outwitted at the RIL board meeting last week, charged that 'Anand Jain's official dealings with Reliance are improper and contrary to ethical norms and this is impacting the business image and reputation of our company.'

Reliance Industries acquired IPCL in May 2002 by successfully bidding for 26 per cent of the government's equity to become the strategic partner. After the open market offer, as mandated, RIL increased its shareholding to 46 per cent.

Dubbing Anand Jain as a 'modern day Shakuni', Anil said that his father late Dhirubhai had always asked the brothers to be cautious against '3Cs -- chamchas, chelas and cronies.'

"Anand Jain is working against the interests of Ambani family and playing an obstructive and negative role in our affairs," he said in the letter.

He also accused Jain, who has no official position in the flagship company RIL, of "spearheading the campaign of character assassination against me personally."

Besides his association with Reliance, Jain has been on board of trustees of Mumbai Port Trust twice for two years each, last time being April 2002 to March 2004, and was on the Jawaharlal Nehru Port Trust from April 1994 to March 1995.

Jain is a Bombay University graduate and has done a course in risk management at London Business School.