If I tell you John Constable’s reputation is on the up, your response may be that it hardly needs raising. The Suffolk-raised, Hampstead-dwelling painter has spent much of the past 200 years as Britain’s Favorite Artist, with iconic works such as "Flatford Mill" and "The Haywain" seen as the embodiment of a humane, unfussy approach to the mellow English landscape that every British person - okay, every English person -regards as their birth right.

At the same time, however, critics have come to see Constable as the epitome of dentists’ waiting room art: stolid, cliched, even a touch philistine in its apparent lack of interest in anything other than the trees and sky that were actually in front of him.