The UK comprises of 4 different countries, England, Wales, Scotland and Northern Ireland. The official name of the UK is The United Kingdom of Great Britain and Northern Ireland. Great Britain does not include Northern Ireland.

Facts about the UK

Population- 60.2 million (2005)
Official Language - English
Capital- London
Area- 242,514 sq km
Main religion- Christianity
Currency- Pound Sterling (£1.00 equals 100 pence)
Life expectancy- 76 (men) 81 (women)
Main exports- Chemicals, foodstuffs and manufactured goods
Head of State - Queen Elizabeth II

England

England is the largest country in the UK, and covers about two thirds of the land. England is home to more than 84% of the population of the UK.  
National Day- St George's Day (23 rd April)
National Emblem - The Rose
National Flag - The St George's Cross, a red cross on a white background
Capital- London

Wales

Wales is called Cymru in Welsh.   It is located to the west of the UK.   Welsh people are often fiercely patriotic, and all signs in Wales are printed in both English and Welsh.
National Day - St David's Day (1 st March)
National Emblem - The Leek and the Daffodil
National Flag - The Welsh Dragon, a red dragon on a background of white over green
Capital - Cardiff

Scotland

Scotland is to the North of the UK, and has the lowest population density of the UK. Scotland also have their own language, Celtic, although it is more common to hear English being spoken. Scotland is distinct from the rest of the UK, in that they have their own education and legal system
National Day - St Andrew's Day (30 th November)
National Emblem - The Thistle
National Flag - St Andrew's Cross, also known as the Saltire, a white diagonal cross on a blue background.
Capital- Edinburgh

Northern Ireland

Northern Ireland is the only part of the UK that is not attached to the mainland. Northern Ireland was the scene of many troubles over past decades, relating to the IRA (The Irish Republican Army) who wanted autonomy for Northern Ireland.
National Day - St Patrick's Day (17 th March)
National Emblem - Northern Ireland doesn't have an official emblem. The Shamrock is commonly used, which is the symbol of St Patrick, and also The Red Hand of Ulster, although this is more synonymous with the Unionists.
National Flag - The Union Jack, which is the National flag of the UK.   It is made up of the flag of St Patrick (a red diagonal cross on a white background) and the English and Scottish flag
Capital - Belfast