The Berne Convention

The Berne Convention is an international agreement that gives copyright protection to literary and artistic works in all countries who are members of the union.
 
Countries all have their own copyright laws which can vary from one country to the next and apply only to the work of authors who are nationals of that particular country. The adoption of the Berne Convention gives an author from one country of the union the same rights in all other countries which are members of the union.
Terms of the Convention also give the author exclusive rights such as the right to authorise translations of their work, the right to authorise arrangements or adaptations of the work and the right to adapt or alter the work.
As the writer you also have moral rights such as the right to be credited as the author of the work and a right not to have your work treated in a 'derogatory manner'. That means things like alternative lyrics or parodies which 'mutilate the work in a manner prejudicial to [your] honour or reputation'.

It can also mean the use of your work as background music in an adult film or in an advert for a product you don’t want to be seen to be endorsing.
The Berne Convention states all works, with the exception of photographic and cinematographic, will be protected for at least 50 years after the author’s death; countries are free to provide longer term of protection.
As of July 2006, there were 162 countries party to the Berne Convention: the UK is one of them.