Separate rules apply for different categories of visitor, dependent on the reason for the visit. These categories are: Visit, Study, Work, Join Family and Transit.
The nationality of the visitor affects the need for a visa. European Union nationals do not require a visa.
The visitor's country of residence affects the need for a visa and type of visa required.
The UK Border agency website provides an interactive "Do I Need a Visa?" questionnaire. The questionnaire informs the visitor of the specific visa required. Applicants from some nations may apply online.
Fees vary, depending on category of applicant. The fee schedule ranges from no-fee (e.g. visiting diplomats) to £675 (roughly $1,000 U.S.dollars) for those seeking permanent residence. Fee information is accessible on the website.