Thirty-two pages of tick boxes. On a Sunday! Why on earth do they need to know if any member of your household has an ONC, OND or RSA advanced diploma? What business of theirs is it if you have disability problems related to old age? Who cares if you are Sikh, Scottish, or consider yourself British or English? Why doesn't the Government mind its own business?
By today, at least one member of your household should have read through and completed your census form, so hopefully you know what I'm talking about. You might want to know why the Government wants to know all these things.
The census is still, at heart, a basic count of the population. Each of the last two censuses found that there were a million fewer people living in the country than we had thought. We are very good at counting when people are born and die in Britain. We are quite good at counting when they come in. We are appalling at counting people as they leave.
There are two alternatives to the census. Anarchy, or a population register. With no census we have no information to use for planning. We have no forewarning that more schools will be needed in particular areas, we cannot tell if the young people are leaving these shores in greater numbers, or if we are welcoming in more folk from overseas than ever before.
The political far-right dream of a return to a time before the first British census of 1801. They dream of a night-watchman state – where government is responsible only for policing the people and protecting private property.
In such a future, there is no planning. Free schools are opened by parents when they see a demand and only if the parents are up to it. If they don't have the gumption, then their children don't deserve a good education.
There is no need to know where the population is ageing the fastest and where health remains poorest and hence, where future needs will be greatest. At first you make general practitioners health commissioners and then you devolve those commissioning decisions down to an individual contract between doctor and patient. You don't need a census if you do that. But people suffer.
One alternative to the census is a purer, freer market. Privatise the universities and we need no longer concern ourselves with how well or poorly educated the population is, nor ask about any of those qualifications.
Another alternative is a population register, and many countries in Europe have one. In parts of Scandinavia, it is opened to the public to consult, and even includes individual's tax records, so you can see what your neighbours earn. Such a system works better than the census, but requires a degree of social solidarity and trust that Britain lacks. Ultimately, you have to trust that a government has your best interests at heart and to collaborate with a population register, notifying the authorities every time you move home and every time you leave the country, so they can take care of you, if needed.
A state population register is also not what ministers are proposing, in their search for a cheaper alternative. What they suggest is that a private-sector organisation, like a credit reference agency, expand its remit with a little help from government. Already two major credit reference agencies are given access to the full electoral roll, including the names and addresses of those who ticked that they did not want their name and address made public.
If there is no census in 2021, then the state will rely on the kind of firm that shops use to check your credit rating when you are offered a store card. These outfits collate the electoral roll with county court judgment records and many of the other bits of trivia about you that are released when you tick the box to say "share my records". Credit reference agencies are very good at maintaining a list of people who look like safer bets to furnish with loans. They are near to useless at recording the whereabouts of children, at differentiating between groups of the public with differing needs, but not differing needs for credit. They are interested in profit, not planning.
So, when you get to page 32 of your form and think, why on earth do I have to ask Aunt Mabel her date of birth, she's only visiting for the night, don't they know she's a bit sensitive about her age ... take a few seconds to consider the alternatives to the decadal census – and also some of the surprising things the census tells us.
Who, for instance, make up the largest group of immigrants to Britain, and living in the greatest concentration, who have brought their children to raise in this country? They are not from India or Pakistan, but America. One in seven of the children growing up in some of the most affluent neighbourhoods of central London was born in the United States. They are the children of diplomats, businesspeople and bankers, and they indicate an area likely to be wealthy.
On the other hand, areas which have a high proportion of German-born adults (the children of soldiers serving with the army of the Rhine) tend to be economically depressed places where the best option was, and remains, enlisting in the Army.
It is only the census that can show us that the more we have our hearts broken, the nearer we tend to move towards the sea. Those who divorce are more likely to move out of cities than others of a similar age. Those who have remarried are even more likely to have moved further away from the metropolis than other peers. Heartbreak often involves home relocation, but there must be more to it than that for the exodus to be so coordinated. It is because of these moves that step-children are most concentrated in the countryside and that so many of our second- and third-time married folk live on the South Coast.
Over the long term, the census lets us assess whether the country is polarising or coming together socially. And it lets us look up our great- grandparents, wonder at their lives and construct our family trees.
Even the land of the free, the United States of America, is keeping its decadal population census. The British government's current spending plans are to cut the proportion of GNP spent on the public sector by 2015 to less than that spent in almost any other affluent nation – lower than the already low-spending USA. This is why the Americans can still afford a census but our government says we cannot – not because we don't have the wealth, but because it does not want the state to spend so much of affluent people's money on the planning for all of us.
After today, we may not be all in it together any more.
Danny Dorling is professor of human geography at Sheffield University. His new book, based on the census, So You Think You Know About Britain, is published by Constable at £8.99