London is the capital of the United Kingdom of Great Britain and Northern Ireland, situated on both sides of the Thames River; it's the political, financial, commercial, industrial, and cultural centre of Great Britain. It is the largest city in Europe with the total population of about 8 million people (over 12 million with the suburbs). About one fifth of the total population of the UK lives in Greater London, that is in London with its suburbs.

London is home for the headquarters of all government departments, Parliament, the monarch and all the major legal institutions. It's the country's business and banking centre and the centre of its transport network. It contains the headquarters of national television networks and of all the national newspapers. The financial services sector is a major source of overall employment in London.

Consumer goods, clothing, precision instruments, jewelry, and stationery are produced in London, but manufacturing has lost a number of jobs in the once-dominant textile, furniture, printing, and chemical-processing industries as firms have moved outside the area. Engineering and scientific research are also important to the economy, as is tourism. The city is a centre for road, rail, and air (its airports include Heathrow and Gatwick), and it is now linked to the Continent by a high-speed rail line under the English Channel. London still remains one of the world's greatest ports. It exports manufactured goods and imports petroleum, tea, wool, raw sugar, timber, butter, metals, and meat.

The original walled city of London (then Londinium) founded by Romans was quite small. In the Middle Ages it did not contain the Parliament or the royal Court, because it would have interfered with the interests of the merchants and traders living there. It was in Westminster, another city outside London's walls, that these national institutions met. Today, both 'cities' are just two areas in Central London. The City is London's commercial centre; it is also referred to as the "Square Mile of Money' because of its area. The Bank of England, Lloyd's, the stock exchange, the Royal Exchange and numerous other banks and investment companies have their headquarters there. The City of Westminster contains London's most famous tourist attractions: Westminster Abbey, the Houses of Parliament and so on.

Other well-known areas of London include the West End and the East End. The former is one of the main tourist attractions of London, where Buckingham Palace and quite a number of world-famous museums are located. It is famous, too, for its theatres, luxurious hotels and restaurants, and expensive shops. The latter is known as a poorer residential area of London.

Central London makes up only a very small part of Greater London. The majority of Londoners live in its suburbs, millions of them commuting into the centre every day to work.

London is a cosmopolitan city. People of several races and many nationalities live there. A survey carried out in the 90s found that 137 different languages were spoken in the homes of just one district of London.