Constable first started to plan a large canvas about the opening of Waterloo Bridge around 1819, but over the years his ideas about how to treat it changed. Originally he intended to focus on the royal embarkation at the foot of Whitehall Stairs. However, in the finished picture, shown here, this recedes into the middle distance, and the sky and river both assume greater importance.

This was the largest of Constable’s exhibition canvases. It owes a debt to the Thames subjects of Canaletto and the great ‘historical’ landscapes painted by the seventeenth-century French artist Claude Lorraine.