The essential protection of software stems from intellectual property rights, primarily copyright. When the United Kingdom left the European Union, at a superficial level nothing changed, because the essence of copyright is based on International Treaties. All the countries within Europe, and indeed most of the world have signed up to those International Treaties, which to a large extent harmonise the law of copyright globally. There was little scope for change just because the United Kingdom was leaving the European Union. Not all the countries in the world unequivocally accept that copyright extends to protect software. However, software has been afforded full copyright protection in Europe since 1993 when a harmonising directive - Directive of 14 May 1991 on the Legal Protection of Computer Programs which was re-enacted without significant change in a Directive having the same title on 23 April 2009 - came into force. Due to this Directive, the law of copyright, as it applies to software within Europe has been harmonised to an even greater extent than is required by mere membership of the international Copyright Treaties.