One of his largest and most recognisable works is the double portrait of two thoroughbreds in a wide landscape, showing Sir Hercules and Thorngrove.
In 1819 the Royal Academy of Arts accepted a picture of him for exhibition and shows that at that time Hancock was residing at 55, St. James's Street in London.
But at the exhibition of 1821 he was represented by The Broken Teapot, a title which suggests that he only later in his life turned his attention to the sporting field.
He became so popular that for a number of years he was commissioned to paint Derby winners which forms an important part of his work.
It was at that time when Hancock's paintings of horses came to the attention of the proprietor of The Sporting Magazine and, more importantly, to Rudolph Ackermann in Regent Street.
Hancock succeeded John Ferneley in supplying paintings of Derby and St Leger winners to Ackermann who was publishing prints of these classic racehorses in competition with S. & J. Fuller at the time.