I'm not sure about the UK, but to register a copyright generally cost US$45 [in the case of US, but Copyright is generally applicable to everywhere; In the US, it is much more easier to obtain a copyright.]. You can register an official copyright via the US Copyright office. Copyrights expire after a fixed time [~50-70 years after the author's death]. I'm not sure about the renewal of a copyright though.
*Copyright is usually automatic, but if you register a copyright, you gain additional benefits.