David Olusoga on the census: 'Some see it as a civic duty, and they're right'

UK historian prepares online lesson for 1.5m children on population survey's role in tracing the past and looking to future

As a child growing up on a council estate in Gateshead, the historian David Olusoga remembers his mother filling in a lengthy form about their family: ages, occupations, how they travelled to work, birthplace, language, religion, whether they owned or rented their home. I wanted to know what this thing was," he says.

Now, he describes the census as a snapshot taken every 10 years. It's like somebody suddenly turns on the light - and you can see everybody, where they are."