Smokescreen by Dick Francis (1972)

Edward Lincoln has scaled the Himalayas, survived car chases and defeated scores of assassins. As a movie action man he’s even suffered stoically at the hands of sadistic directors.

After finishing his latest film, he visits South Africa to discover why a dying friend’s horses are suddenly failing on the race track. Lincoln’s attempt to help a friend soon puts him in harm’s way.

This story suffers from a very long buildup. There are only two incidents of intensity. And the one at the end could be predicted from the first scene. So not one of his best.