Britain’s forgotten impressionist, whose genius lay undiscovered in an attic for decades

How does art endure? The painter John Louis Petit had no need to sell, did not exhibit his work professionally and most of it was forgotten until the death of his grandniece. At that point it was found in an attic by new owners clearing the house and off-loaded into auctions. Now, Philip Modiano has founded a society in Petit’s honour and written a book, ‘J. L. Petit: Britain’s Lost Impressionist’. Huon Mallalieu looks at a man who was skilful and prolific watercolourist, as well as an ecclesiastical architecture writer who…