The UK Population
Visit the UK's Office of National Statistics to find out about the population of the United Kingdom
The Global Population
Visit the Population Reference Bureau to find out up to date facts and figures about global populations. The 'World Population Data Sheet' is particularly informative!
Specific Country Information
The CIA in America publish detailed information about the population, development, economy, politics and environment of every country in the world. The UK is about the size of Oregon. Take a look!
The United States Census produces population pyramids for every country. You can look at the current population pyramids and see how the population structure of different countries is going to change over the next 40 years.