A UK visa is the authorizing document that gives worldwide citizens the right to enter, stay temporarily, or live forever in the territory of the UK. It is often either a document provided by a UK consulate or embassy in your country of residency or a stamp you receive in your passport. The earliest one can apply for a UK visa is three months before the date of the intended trip. Although the processing of visa applications may take up to three weeks. An advance application can give a person enough time to the consulate for the processing of a visa.