MUMBAI: Nusli Wadia , longtime associate of Rata Tata and independent director on the boards Tata group companies like Tata Chemicals, Tata Motors and Tata Steel, has filed a Rs 3,000-crore defamation suit against Ratan Tata and Tata Sons.Officials close to the development said the chairman of Wadia Group has sought compensation from Tata Sons for the various accusations it levelled against him in public statements to shareholders. He says no valid reason was given for the allegations and the extraordinary general meetings (EGM) called by the group for his ouster.Wadia had in November threatened civil and criminal defamation suit against Tata Sons, when the company alleged that Wadia was acting in concert with Cyrus Mistry and against the interests of the principal shareholders by galvanising independent directors.Relations between Wadia and Ratan Tata go back decades, and both have waged many a corporate battle in the past. Wadia said Tata Sons has failed to furnish any evidence to prove the allegations made against him in the special notice to remove him from the boards of Tata Steel, Tata Motors and Tata Chemicals. He also said Ratan Tata had failed to live up to the high standards of ethics, morality and corporate governance set by JRD Tata. Tata Sons declined to comment on the development.Tata Sons has been waging a war against its former chairman Cyrus Mistry since October 24. Over the last few days Mistry has been removed from the boards of Tata Industries, TCS and Tata Teleservices.Over the last two months both camps have been hurling various allegations at each other.