The new inquiry led by a former Supreme Court justice will focus on how the broadcaster obtained the interview and whether executives covered up any wrongdoing.

"The independent investigation is a step in the right direction," William said in a statement on Wednesday.

"It should help establish the truth behind the actions that led to the Panorama interview and subsequent decisions taken by those in the BBC at the time."

During Diana's interview with journalist Martin Bashir, watched by more than 20 million viewers in Britain, she shocked the nation by admitting to an affair and giving intimate details of her failed marriage to heir-to-the-throne Prince Charles.

This month, her brother Charles Spencer said the BBC had failed to apologise for what he said were forged documents and "other deceit" which led him to introduce Diana to Bashir.

The BBC's Director General Tim Davie said the broadcaster was determined to get to the truth about Spencer's claims.

Spencer says Bashir made a series of allegations to himself and his sister such as that Diana was being bugged by the security services and that two senior aides were being paid to provide information about her.

He says Bashir provided fake bank statements to back up the claim.

Others involved in making the program have also come forward to say the BBC had covered up wrongdoing.

Bashir has made no public comment to media and the BBC says the journalist, who gained global renown from the Diana interview and is the corporation's religious affairs correspondent, is currently on sick leave, recovering from heart surgery and from contracting COVID-19.

The BBC said its investigation would examine five questions such as what steps the BBC and Bashir took to obtain the interview

They include the mocked-up bank statements purporting to show payments to a former employee of Earl Spencer, purported payments to members of the royal households and other matters raised by Earl Spencer.

Australian Associated Press