If you are not an UK or EU citizen and you are planning to visit and/or move to London, you have to make sure your paperwork is in good order. Check with your local UK embassy or council before you travel or you'll can be refused entry at the border and returned back home. (In some occasions you won't even be allowed to leave your own country!)

There are many companies that help you with your VISA paperwork. If you came here with a VISA in the correct order and its duration is about to expire, you can apply for extensions or changes in the VISA depending on various factors. It is a complex, long and sometimes expensive process that you better start way ahead of your expiry date if you don't want to be kicked out of the country!

Read all about it here

Embassies
This is the official list with the details of the VISA application office in every country

Is always good to register with your own embassy or consulate, read about it here, specially if you are an student - you can find the website of each embassy here