A Rolls-Royce Silver Ghost shooting brake thought to have been used to secretly transport Wallis Simpson to and from Balmoral Castle is to auction at H&H Classics.
The lot is valued at up to £100,000-120,000 ($152,530-183,036) ahead of the June 20 sale.
Wallis Simpson was an American socialite who became romantically involved with Edward VIII in 1934.
However, the fact she had been married twice already proved controversial, and Edward was forced to abdicate in 1936. They eloped in 1937.
The car belonged to Edward and would likely have been used from the start of the couple's affair.
Damian Jones, sales director at H&H, commented: "A shooting brake was really a utility vehicle, designed to go down unmade roads and very rough tracks to get people to the best possible vantage points for the shoot.
"It is not something you would usually associate with a member of the royal family using covertly. It's like a member of the modern royal family sneaking around in a delivery van.
"There are black silk pull down blinds in the back and there were rumours these were to smuggle Wallis Simpson in and out of Balmoral…
"The car was used for trips to remote parts of the Scottish countryside where he would have effectively been in the middle of nowhere and privacy wouldn't usually be an issue. So the curtains add to the intrigue."
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