The 1801 Census counted 10.5 million people in Britain - the population 200 years later is about 60 million. There has been a Census every ten years since, except during the Second World War in 1941. Every household in the country has to return a census form. One is delivered to every home in England, Scotland, Wales and Northern Ireland. A total of 342 people were prosecuted for not completing their forms in 1991.
Information is gathered on everyone living in the household, including new born babies.
In England and Wales, the census is planned and carried out by the Office for National Statistics. Elsewhere it is the job of the General Register Office for Scotland and the Northern Ireland Statistics and Research Agency. Almost 70,000 people, called enumerators, will be involved in counting the UK's population this year. The Census form has 40 questions in England and 41 in Wales. The first set of questions are about accommodation and relationships within the household and are answered by the householder.