If you live outside the European Union, you will almost certainly be classed as a visa national and will need to obtain a visa before you can study in the UK.
If you are a European citizen living within the EU, you will not need a visa to student in England.
If you are classed as a visa national, depending on the length of time you wish to study you may require a student visitor visa or a general student visa.
The UK government is currently making changes to the student visa system, and there will be new eligibility criteria for issuing student visas.
For the latest information and guidance, we suggest you visit the UK Border Agency website.