Cadbury have been trying to keep the color purple all to themselves.
From the Lawyer:
Cadbury has exhausted all avenues to copyright the colour purple after its application to appeal was refused by the Supreme Court.
The chocolate maker was refused the chance to register its iconic purple shade – otherwise known as Pantone 2685C – when Lords Neuberger, Wilson and Hughes found it did not raise an arguable point of law.
The March judgment brings an end to the bar wars between Nestlé and Cadbury, which had squared off over whether or not the chocolate giant could block other companies from using the colour for their sweet wrappers.
More details, if you are into the boring legal stuff, available here.