Noel Carrington, London, 1947, 143 pp, illus Lionel Edwards
Note: the first edition states it was published in 1927, but this is a mistake as the author was only two at the time! The true publication date is 1947. Thanks to Caro Newland for pointing me in the right direction here.
Topper is the life story of a Welsh pony, from his promising beginnings through the usual descent and back to caring and comfort.