 Unfortunately, it was claimed by a Mr Coco that the Clark power unit was very similar to his own design which he had been trying to sell to Clarks for several months in 1967, before being informed that his design driving the rear wheel by friction caused unacceptable wear to the rear tyre and would not therefore be used.By the time the machine appeared on the market, it had a different drive mechanism but it was apparent that the power unit was closely related to the Coco design, so the designer sued for breach of confidence in that the drawings and prototype engine had been supplied to Clark for evaluation.The resulting case, Coco v AN Clark (Engineers) Limited, remains a fundamental statement of the principles of law in this area.