If you need a United Kingdom visa you must apply for one before you travel to the United Kingdom. Even when you hold a visa you will still need to pass through immigration control when you arrive. But if you are holding a visa you will not be refused perMission to enter unless there has been some change in your circumstances or you gave false information or did not disclose important facts when you obtained the visa. Holders of visas may also be refused on medical grounds, if they have a criminal record, if they are subject to a deportation order or if there are other exceptional reasons why they should not be admitted.

If you are a national of one of the countries listed in leaflet INF 1 or if you are stateless or hold a non-national travel document or a passport issued by an authority not recognized by the UK you must have a valid UK visa on each occasion you enter the UK, unless you qualify for exemption as explained in INF 1. It is not possible to switch from visitor to student status once in the UK. You must therefore have the correct visa before you travel.

Other nationals (such as those from the European Union) do not have to have a visa to study in the UK. However, you will have to satisfy the immigration officer on arrival in the UK that you qualify for entry. If you are in any doubt about your eligibility you are advised to apply for a visa before you travel.

If you wish to apply for an entry clearance you should fill in form IM2A (and related forms if applicable) which you can get free of charge from the nearest British Mission offering a visa service. You can only apply at the British Mission in the country where you are living. Where there is none in the country concerned, or it does not offer a full service, another British Mission will have been designated to handle applications.
Your application form may be submitted by hand or by post together with:
Your passport*
Two recent passport-sized photographs
The visa fee, which is non-refundable
Any relevant diplomas or educational certificates which you hold
A letter from the University, College or School confirming your acceptance for the course of study in the UK and a statement of charges for the course
Evidence of Government sponsorship (if appropriate)

The visa officer may then be able to decide your application without further enquiries. However, you might have to attend an interview. In addition to the documents listed above you may be asked for:
evidence of funds to pay for your stay and your course of studies in the UK or
a letter from your host or sponsor in the UK to say that s/he will support and accommodate you during your course of studies, together with evidence that s/he can do so.