The painted fibreglass head, with felt eyes, was sold on the online auction site by London-based miss-p73, who said in the item description that it had been given to her family in the late-1970s when her father worked for a studio transport company. She added that the accompanying foam rubber hat had long since perished, and said that the mask had been "much loved and played with" in her youth, which had led to it being "a bit chipped and scraped".
After 51 bids the prop - which was only available to buyers in the UK - finally went for £5,154 when the auction ended on Thursday 5th September just after 10.25pm.
The carnival masks were worn by the Autons to disguise their true nature as they handed out deadly plastic daffodils to unsuspecting members of the public.
The four-part adventure started Jon Pertwee's second series as the Doctor. Written by Robert Holmes and directed by Barry Letts, it aired between 2nd and 23rd January 1971. Not only did the story feature the second appearance of the Autons in the show, it also marked the debuts of Katy Manning, Roger Delgado, and Richard Franklin as, respectively, Jo Grant, the Master, and Captain Mike Yates.
With Thanks To Tony Clark