This is Britain, BBC Two

The history of the census is a fascinating one. The Babylonians and the Chinese held censuses mainly for military and taxation purposes, and Egyptians in order to organise the huge number of people required to build the pyramids and to redistribute land following the annual flooding of the Nile. Christians, meanwhile, give thanks for the census that recorded the birth of Jesus of Nazareth; during the five-yearly census ordered by Caesar Augustus, which required every man in the Roman Empire to return to his place of origin, Joseph and the heavily pregnant Mary had travelled to Bethlehem, finding no room at the inn, full as it was with others there for the same purpose.

Britain took rather longer to get around to counting the population, as this thoroughly entertaining programme, full of fascinating “did you know...?” factoids, explained ahead of tomorrow's big box-ticking exercise. Presenter Andrew Marr explained that although the Domesday Book of 1086 could be considered the first census in the British Isles, it wasn’t until 1801 that the UK had a thorough, nationwide population count, its primary purpose to see how many men were available to fight Napoleon.

As each census has been gathered since, the information has been used more broadly with social planning, healthcare, taxation, town planning and immigration predicated on both the actual information and the projections worked out by demographers. For instance, in 1911 there were 100 centenarians and now there are a whopping 12,000, and many more predicted for 20 years' time. As Marr wryly observed, “The Queen is in danger of getting writer’s cramp.”

What followed was a brief history of census landmarks with their significance in telling us about the British and how they have lived - in 1891 respondents were asked how many rooms they had in their home (poverty, overcrowding, large families), in 1911 their occupation (the disappearance of trades and industrial work), in 2001 their religion (leading to 390,127 oh-so-funny responses of "Jedi Knight"), and in 1966 if they owned a car (increasing affluence and the growth of the commuter belt). Oddly, though, Marr didn’t explain why there was a census outside the normal 10-year cycle; since you ask, it was to trial a different method of enumeration.

In 1841 people were asked for the first time where they were born, and allowed entries only for England, Scotland, Wales or Ireland, with everywhere else listed - much to Marr’s amusement - under “foreign parts”. This segment was linked into the current discussion about ethnicity questions on the 2011 census and how the increasingly diverse UK population see themselves as hyphenates - British-Asian, for example. By the way, did you know that in the 2001 census the fourth-largest group of people born outside the UK took their first breath in Germany? But it’s a statistical blip, as the majority of those individuals lived in Colchester, Aldershot and other garrison towns - in other words they were born to parents serving with the British Army on the Rhine in the Cold War years, a vignette that was wittily given a Dad's Army-style invading arrows graphic.

We also learned about the mystery of the disappearing young men in the 2001 census - they had gone abroad to find work - and therefore that we're very good at counting how many live in the UK but don't keep definitive records on those who leave the country each year. The most sobering item was on the disgraceful gap between the ages when rich and poor people die - a massive 40 years for Glaswegian men, about the same as existed in 1911.

Marr has long been a respected political interviewer, but now, following the success of The Making of Modern Britain, he’s the BBC’s go-to man when they want a presenter for a broad-sweep social-history programme and he fronted This is Britain with his usual enthusiasm without hogging the camera. Director and producer Robert Murphy added inventive visuals, interesting input by various experts and the odd vox pop; what could have been a run-through of dry statistics was given real life and subtle social comment.

• Watch This is Britain on BBC iPlayer
• Find Andrew Marr on Amazon