Strachan v Prinsloo  Strachan v Prinsloo is an important case in South African contract law. It was heard in the Transvaal Provincial Division by Tindall J and Greenberg J. An agreement between Strachan and Prinsloo imposed on the former the duty of managing the latter's farm so as to relieve him of all duties of supervision. In spite of warnings, Strachan persistently and continuously failed to attend early in the morning and late in the evening, which was when important duties of supervising had to be done, with the result that those duties had to be performed by Prinsloo. Finally, on three successive days, Strachan did not appear on the farm at all, whereupon Prinsloo cancelled the agreement. The court held  failed to perform a vital term, express or implied, of the agreement;  A serious violation of duty by one party, in other words, justifies the other in terminating the contract.