This piece bears the mark for workmaster Mikhail Perchin (maker of all but three of the imperial Easter eggs) and can be dated to c.1899-1903. It has excellent provenance, having been in the same family since it was purchased in 1929 from Wartski in London for £75.
It will be offered at the silver, jewellery, Asian art, antiques and interiors sale on September 10.
Sedan chairs are among the rarest objets de fantasie produced by Fabergé (fewer than 10 are known). Workshop ledgers document one purchased by Nicholas II in 1896 for 900 roubles.
Another in guilloché enamel, bought from Fabergé by the Dutch rubber magnate Maximillian Neuscheller, was sold at Christie’s in London in 2017 for £700,000.
The Cirencester example is that pictured in Kenneth Snowman’s 1962 ‘bible’ The Art of Carl Fabergé.
Auctioneers Elizabeth Poole and Lindsey Braune commented: "Discovering the sedan chair in Kenneth Snowman’s book was rather a spine-tingling moment. It belongs to a family who collected some absolute gems in the early 20th century – and have looked after them ever since."
The sedan chair is estimated at £60,000-80,000.