Prince Philip's UFO investigation could be released following the death of Queen Elizabeth.
The prince developed a fascination with aliens after a bricklayer reported a close encounter with extra terrestrial life at the home of Lord Louis Mountbatten, Philip's late uncle - but until now, his investigative work into UFO sightings in the UK has remained under wraps.
Philip - who died in April 2021, aged 99 - has been credited with creating a so-called Royal X-Files on the subject of space and alien life.
And the royal family are now facing calls for the investigation to be made public, the Daily Star newspaper reports. The work previously remained a secret during the reign of the queen.
Nick Pope, the ex-Ministry Of Defence official who was in charge of the UK government’s UFO desk between 1991 and 1994, claims that Philip and Sir Peter Horsley - his ex-RAF associate - spent years investigating alien sightings.
He said: "[Philip] kept an eye on developments, subscribed to UFO magazines and newsletters and had witnesses interviewed."
He also claimed Philip's interest in the subject was deliberately kept under wraps during the reign of the late monarch as it would've caused a stir.
Nick told 'History TV': "This is highly sensitive. Here you have the queen’s husband investigating UFOs. Had the news got out it would have caused a sensation."
Lord Mountbatten - who was assassinated in August 1979 - and Prince Philip are said to have "talked extensively" about the possibility of extra terrestrial life.
And Richard Dolan - an expert on the UFO subject - is convinced that the late monarch was aware of the conversations between Philip and his uncle.
He said: "You have to assume Queen Elizabeth knew."