Since everyone seems so confused: Britain is the historical term for the lands conquered by the Romans, which consisted of England, Wales and only a small part of southern Scotland. Colchester was the original capital during this time period, but Londinium later became the capital due to the strategic position on the Thames River. And Londinium became London in modern day. There is no modern day capital of Britain, because it's not a country. Great Britain is the name of the island that includes England, Scotland and Wales. The UK is a country that consists of the autonomous regions of England, Scotland, Wales and Northern Ireland. Thus the full name being the United Kingdom of Great Britain and Northern Ireland. England, Scotland, Wales and Northern Ireland do not fit the definition of a country on their own, but the UK does. The British Isles is the name of the geographic region that includes the islands of Great Britain and Ireland, as well as tons of small islands like the Isle of Man that aren't part of the UK. London is the unofficial capital of the UK (there is no official one), although each of the autonomous regions has its own capital. England - London Scotland - Edinburgh (not Glasgow!! the Parliament building is in Edinburgh) Wales - Cardiff Northern Ireland - Belfast And the capital of Ireland is Dublin.