The “Self-Portrait of the Artist on a Grey Cob” is one of five paintings by Alfred Munnings expected to sell for more than £4 million at auction at Christie’s in New York on 1 June.

Munnings, whose romantic pictures of horses were first exhibited at the Royal Academy in 1898 is arguably the greatest equine artist of the 20th century.

This collection of paintings belonged to the late Mr and Mrs E Miles Valentine, from Unionville, Pennsylvania, who used to ride with Munnings and his wife, Violet.