Prince William and Prince Harry want the "conclusive findings" of the investigation into their mother's death to bring an end to speculation surrounding the crash.

Clarence House said the brothers were grateful for the thoroughness of the high-profile inquiry into the "tragic accident" that killed Diana, Princess of Wales.

Former Metropolitan Police commissioner Lord Stevens declared that allegations that the Princess was murdered were "unfounded".

A statement from Clarence House, the office of Prince Charles, said Princes William and Harry had received a copy of the report from Lord Stevens, the former chief of the Metropolitan Police who directed the three-year investigation.

"They are extremely grateful to Lord Stevens and his team for the thoroughness and professionalism they have shown during their investigation, and trust that these conclusive findings will end the speculation surrounding the death of their mother Diana, Princess of Wales," the statement said.

Earl Spencer, Diana's brother, and her sisters Lady Sarah McCorquodale and Lady Jane Fellowes, also supported Stevens' findings.

"We have been briefed on the conclusions of the inquiry and agree with them entirely, and look forward to reading the full report in detail," their statement said.