British English is the variety of the English language spoken in the United Kingdom. It is the language in which this project is written, and about which it aims to give advice. Distinguish it from the other varieties of English which exist in the world, such as American English, African English, Australian English, Indian English and so on.
The difference that matters most to most students is that of spelling. When you write in a British university, be sure to use a spellchecker that is set to English U.K. or some equivalent name. British academics will notice, and dislike, English U.S. as the language in which assignments are submitted.