A sculpture by Hans Hackie appears for the next twelve months on the spare plinth in Trafalgar Square.
It is based on a series of engravings of horse skeletons in a book displayed in the Gallery.
There are also several paintings by Stubbs on display there.
The riderless horse of the sculpture has an electronic ticker of share prices displayed on a bow around one of its front legs. Some say a statue of William IV on horseback was planned for the plinth, but the money to pay for it was lost on the stock exchange.