The United Kingdom of Great Britain and Northern Ireland, commonly known as the United Kingdom (UK) or Britain, is a sovereign state in Europe. Lying off the northwestern coast of the European mainland, the country includes the island of Great Britain (a term also applied loosely to refer to the whole country), the northeastern part of the island of Ireland, and many smaller islands. Northern Ireland is the only part of the UK that shares a land border with another state: the Republic of Ireland. Apart from this land border, the UK is surrounded by the Atlantic Ocean, with the North Sea in the east and the English Channel in the south. The Irish Sea separates Great Britain from Ireland. The UK has an area of 243,610 square kilometres (94,060 sq mi), making it the 78th-largest sovereign state in the world and the 11th-largest in Europe.
The total area of the United Kingdom is approximately 243,610 square kilometres (94,060 sq mi). The country occupies the major part of the British Isles archipelago and includes the island of Great Britain, the northeastern one-sixth of the island of Ireland and some smaller surrounding islands. It lies between the North Atlantic Ocean and the North Sea with the south-east coast coming within 22 miles (35 km) of the coast of northern France, from which it is separated by the English Channel. In 1993 10% of the UK was forested, 46% used for pastures and 25% cultivated for agriculture. The Royal Greenwich Observatory in London is the defining point of the Prime Meridian.
The United Kingdom has a temperate climate, with plentiful rainfall all year round. The temperature varies with the seasons seldom dropping below −11 °C (12 °F) or rising above 35 °C (95 °F). The prevailing wind is from the south-west and bears frequent spells of mild and wet weather from the Atlantic Ocean, although the eastern parts are mostly sheltered from this wind since the majority of the rain falls over the western regions the eastern parts are therefore the driest. Atlantic currents, warmed by the Gulf Stream, bring mild winters; especially in the west where winters are wet and even more so over high ground. Summers are warmest in the south-east of England, being closest to the European mainland, and coolest in the north. Heavy snowfall can occur in winter and early spring on high ground, and occasionally settles to great depth away from the hills.
A radial road network totals 29,145 miles (46,904 km) of main roads, 2,173 miles (3,497 km) of motorways and 213,750 miles (344,000 km) of paved roads. In 2009 there were a total of 34 million licensed vehicles in Great Britain.
The UK has a railway network of 10,072 miles (16,209 km) in Great Britain and 189 miles (304 km) in Northern Ireland. Railways in Northern Ireland are operated by NI Railways, a subsidiary of state-owned Translink. In Great Britain, the British Rail network was privatised between 1994 and 1997. Network Rail owns and manages most of the fixed assets (tracks, signals etc.). About 20 privately owned (and foreign state-owned railways including: Deutsche Bahn; SNCF and Nederlandse Spoorwegen) Train Operating Companies (including state-owned East Coast), operate passenger trains and carry over 18,000 passenger trains daily. There are also some 1,000 freight trains in daily operation. The UK government is to spend £30 billion on a new high-speed railway line, HS2, to be operational by 2025. Crossrail, under construction in London, Is Europe's largest construction project with a £15 billion projected cost.