The plaintiff were the manufacturers of the the first commercial windsurfer/sailboard and patented their design for sailboard with a Bermuda rig and a wishbone spar in the UK and elsewhere. In this case the plaintiffs sued another company for patent infringement as a result of making and selling a similar sailboard in the UK.
The validity of a patent can be challenged by an alleged infringer and Tabur Marine based their challenge on the fact that in 1958, at least 10 years before the grant of the patent a 12 year old boy called Peter Chilver had built an early version of a sailboard which was evidenced by film footage taken off the coast of Hayling Island. They alleged that this proved that the subject of the plaintiffs' patent had been anticipated
The Court upheld Tabur Marine's claim that the boy's invention predated the plaintiff's application for a UK patent and the patent was rendered invalid notwithstanding that Chilver's sailboard was of a slightly different design.