Former Olympus Corp. Chief Executive Officer Michael C. Woodford said the company's "toxic" board must go and he would be ready to run the company again if the majority of shareholders wanted him to.

Woodford and Chairman Tsuyoshi Kikukawa are feuding after the Briton publicly questioned $687 million paid in fees for a 2008 takeover. Woodford says he was fired for challenging the transaction; Olympus says he was axed over his management style.

In a new twist Wednesday, Olympus said Kikukawa stepped down and Shuichi Takayama succeeded Kikukawa as president. Kikukawa will remain a director.

Shares in the 92-year-old camera and medical equipment maker have slumped more than 50 percent since the board fired its first non-Japanese CEO six months after he was appointed and promised to cut costs and debt, and overhaul management.

"The board has to go, they're all toxic, they are all contaminated," Woodford said Tuesday, adding he won't step down as a director of the company. "Shareholders have contacted me and their basic message is 'please don't resign.' I would go back if the majority of shareholders choose that."

Olympus, the world's biggest maker of endoscopes, didn't commit any wrongdoing and previous acquisitions were carried out through proper procedures, Kikukawa claimed in a statement posted on the company's website. The firm will disclose information on the matter in a timely fashion, he said.

Woodford said he asked the U.K.'s Serious Fraud Office to probe the fees in the takeover. He is also reportedly cooperating with the FBI.