Although the first official Census was not taken until 1801 there had been a number of previous attempts to estimate the size of the population. The most famous of these was made by a man called Gregory King. He estimated that in 1696 the population of England and Wales was 5.5 million. Debates regarding the size of the population continued throughout the 1700s but it was not until the end of the century that people started to see the need for a full Census.
It has been argued that the first Census was prompted by the publication of a book called Essay on the Principle of Population, which was written by Thomas Malthus in 1798. Malthus argued that the population was growing so quickly that the country would soon not be able to feed itself. The publication of the book coincided with a period of war, bad harvests and food shortages and many people became very worried. How would they know if the country could feed its people if it didn't know how many people it had to feed? This concern may have persuaded the government to pass the Act, which authorised the taking of the first official Census.
As the nineteenth century progressed, it became clear that the government needed to know more than just the overall number of people living in the country. This was reflected in the questions asked by different Censuses. For example, the introduction of a question relating to age in 1821 was designed to find out how many men able to bear arms lived in the country and to improve the tables on which life assurance schemes were based. More detailed questions on occupations from 1831 provided the government with information which could be used to discuss economic theory.
Using the Census to collect information for use in developing government policy has continued to this day. For example, questions in the 1991 Census enabled the government to discover how many elderly people were living alone and what type of accommodation they lived in. By collecting the same information from all over the country it makes it easy for the government to look at similarities and differences between different parts of the country and decide on what action needs to be taken.