The British Library is a research library in London that is the national library of the United Kingdom. It is one of the largest libraries in the world. It is estimated to contain between 170 and 200 million items from many countries. As a legal deposit library, the British Library receives copies of all books produced in the United Kingdom and Ireland, including a significant proportion of overseas titles distributed in the UK. The Library is a non-departmental public body sponsored by the Department for Culture, Media and Sport.

London is the capital and largest city of both England and the United Kingdom, with a population of around 8.8 million, and its metropolitan area is the largest in Western Europe, with a population of 14.9 million. It stands on the River Thames in south-east England at the head of a 50-mile (80 km) estuary down to the North Sea and has been a major settlement for nearly two millennia. The City of London, its ancient core and financial centre, was founded by the Romans as Londinium and retains its medieval boundaries. The City of Westminster, to the west of the City of London, has for centuries hosted the national government and parliament. In the 19th century, London grew rapidly, becoming the world's largest city at the time, as it expanded and absorbed the neighbouring county of Middlesex, and parts of Surrey and Kent. In 1965 it was combined with parts of Essex and Hertfordshire to create the administrative area of Greater London, which is governed by 33 local authorities and the Greater London Authority.