[Excerpt] The purpose of this booklet is to provide a summary of the laws and procedures applicable to entering the UK for the purposes of working and the main employment law obligations on employers. It is not a definitive statement of all the legal rules, but merely an overview of the main legal principles. The law is correct as at April 2006. Where changes in the law to come into force after this date are already known and/or announced these are mentioned in this booklet.