Accountants, investment bankers and former executives have been blamed for a $1.73 billion, 13-year, financial scandal at Olympus, according to an official report.

The findings, unveiled at a press conference in Tokyo in the past few hours, appear to back claims by former CEO Michael Woodford for the complete removal of the Olympus boardroom, clearing the way for him to make a return to the top job.

Woodford, a Briton, was sacked after questioning colleagues over record fees paid to financial advisers in relation to past acquisitions. Olympus claimed Woodford was fired over a clash of management styles.

Olympus?s former vice-president Hisashi Mori and the firm?s ex-auditor Hideo Yamada were the brains behind a scheme that covered up accounting losses dating back to 1998, states the ?independent? third-party panel, commissioned by Olympus and led by a former Supreme Court judge.

However, the investigation found no evidence that the financial malpractice had links to Japan?s notorious ?yakuza? criminal underworld, as has been rumoured in the press in recent weeks, reports Reuters.

?A factor in the longevity of the cover-up was the existence of external players who advised, helped and assisted in the concealment while knowing full well that such accounting practices were illegal.?

External auditors Ernst & Young and KPMG come under fire in the report along with ?several investment bankers?, according to the news agency, quoting sections of the 178-page report.

?The core part of the management was rotten and the parts around it were also contaminated by the rot.

?In the worst possible sense, the situation was that of the tribal culture of the Japanese salaryman,? adds Reuters.

In an interview with Amateur Photographer a few weeks ago, Woodford said the crisis ‘strikes at the heart of a boardroom culture of sycophancy and yes-men‘.

The report, an English version of which is expected to be posted on the Olympus website shortly, adds: ?Olympus must take this opportunity to extract the tumour that centres around its former management group and literally aim to renew its body and soul.’

The investigation is one of several probes into Olympus?s affairs. A joint investigation by Tokyo police, prosecutors and the market regulator has yet to release the results of its findings.

Meanwhile, the FBI and the UK’s Serious Fraud Office are carrying out their own investigations.

Olympus faces being delisted from the Tokyo Stock Exchange if it fails to submit its latest business results, which were put on hold, by 14 December.