The most important thing to understand in UK work permits is that in the UK the employer applies for the work permit and the the work permit is granted for a particular employee. If you are an individual hoping to work in the UK, you cannot apply for a work permit. If you have a work permit for the UK, you can't change jobs without getting a new work permit.

The following are the different kinds of permit to work in UK :

The Business and Commercial Work Permit allows employers in this country to recruit people from outside the European Economic Area (EEA) who are going to be filling a vacancy that may otherwise be filled by a 'resident worker'.
Please use form WP1 when applying for: -
Business and Commercial work permits;
Multiple Entry Work Permits; and
for changes of employment, or use form WP1X for extensions to existing work permits. For Sponsored Researchers use the form SR1 to apply for new, change of employment and extension applications.

The Student Internship arrangements allow students from outside the EEA studying first or higher degree courses overseas to undertake an internship with an employer in this country. Please use form WPSI when making an Internship application. Please see the 'Student Internship guidance for employers' (Student Internship notes) for further details.

The Training and Work Experience Scheme enables people from outside the EEA to undertake work-based training for a professional or specialist qualification, or a period of work experience. Please use form WP1 when applying for Training and Work Experience work permits and for changes of employment or use WP1X for extensions to existing work permits.

The General Agreement on Trade in Services arrangements allow employees of companies that are based outside the European Union to work in UK on a service contract awarded to their employer by a UK-based organisation. This is a special and exceptional arrangement within the normal work permit rules made under the General Agreement on Trade in Services (GATS). The company abroad that is contracted to provide the service needs to apply using the application form GATS-A. Please see the 'Guidance notes for employers on how to apply for a General Agreement on Trade in Services work permit' (GATSA (notes), and associated guidance in GATSB (notes) if necessary) for further details.

The Sectors Based Scheme (SBS) allows employers in this country to recruit people from outside the EEA to fill vacancies that they are unable to fill with 'resident workers'. SBS is sector based and currently operates in the hospitality and food manufacturing sectors. SBS only covers those posts within a given sector that are recognised as hard to fill by UK Work Permits, and are specified in the Sectors Based Scheme Guidance Notes. The posts specified in the guidance notes are at a level that would not meet the skills criteria of the Business and Commercial arrangements, but which have been identified as hard to fill within the UK. The SBS is quota based. Please use form SB1 when applying for an SBS work permit or a change of employment under these arrangements or form SB1X for an extension to an existing work permit.

The Sports and Entertainments arrangements allow employers in this country to employ established sportspeople, entertainers, cultural artists and some technical/support people from outside the EEA. Please use form WP3 when applying for Sports and Entertainments work permits, Multiple Entry Work Permits and for changes of employment or use WP3X for extensions to existing work permits.