English is the official language of the United Kingdom and it is estimated that 95% of the population speak it at a native level. In addition, it is the most widely spoken language internationally, so many people, both young and old, travel to the british capital just to learn this language. You have all the information in: «What is the language of the UK? What accents and dialects does it have?«.
You have all the information in: "What is the language of the UK? What accents and dialects does it have?".