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The subject of this small-screen drama (to be aired in August) was a Chambre Automatique De Bertsch or Chambre Microscopique – an instrument in which the camera and the microscope were effectively combined.

Relatively little is known about the Paris photographer, inventor and optician Auguste Adolphe Bertsch (born c.1813, he was killed during the Paris Commune of 1871) but his specialty was the micrograph – a photograph that could accurately record what had previously been seen only through a microscope or by artistic rendering.

In 1851 he photographed lice, antennae of flies and crystals and in 1853 presented his research at the Académie des Sciences. Salt prints of his work with titles such as Pou de l’abeille domestique grossiment 300 diametres (lice of the honey bee magnified 300 times) are held by a number of international museums.

Remarkably, the instrument had been bought earlier in the month by Carlisle auctioneer and valuer Paul Laidlaw while a contestant on the 15th series of Antiques Road Trip. It had cost under £100 from a shop on the Kent coast.

It was in good condition and retained both the brass wet plate fixed-focus camera (serial number 229 for c.1861) and a quartet of reagent bottles that would have allowed for use while travelling.

Ed Crichton, fine art manager at Lacy Scott & Knight, had been amazed to see it arrive alongside nine less distinguished objects.

Exact comparisons were hard to find but a much larger and more extensive ‘chambre automatique’ by Bertsch formed part of a sale held by Vienna camera specialist WestLicht Photographica in May 2013. It had sold for €150,000 (plus 20% buyer’s premium).

“It really shouldn’t have gone into a general sale but that is the rule of the show,” said Crichton. It was only online for three days but we wanted to do it justice so contacted the right people. In the end it sold to a private collector in Switzerland bidding via thesaleroom.com.”

It is a record profit (the money is donated to charity) for the show, smashing the previous best: a Tibetan bronze bodhisattva bought for £50 by Anita Manning of Great Western Auctions and sold for £3800 last year.