The museum found the picture on Langston’s website.
The c.1820, 2ft x 19.5in (61 x 49.5cm) oil on panel is thought be by the English portraitist Henry Wyatt (1794-1840) – a student of Sir Thomas Lawrence. It was offered in a period gilt frame for a price around £8500.
Gell was an archaeologist and classical scholar whose circle of friends included Lord Byron and Walter Scott. A member of both the Society of Antiquaries and Society of Dilettanti, he published extensively on topography and antiquities.
Boosted by a recent donation from the Society of Dilettanti, the BM has a body of Gell’s work including sketch and notebooks recording his travels and his life living in Italy after 1815.