What is the population of the world? Perhaps 6,498,912,078. And in Slough? Maybe 117,600. And what do these two numbers have in common? They're both wrong. Counting population accurately is impossible – globally or locally. Any statistician will agree and explain how they carve out a model of ‘best fit' for the areas they need to cover. That's standard practice. But it does have limitations, especially for those who are nowhere near this line of best fit.

As population estimates are increasingly used in planning policy and determining government resources, surely there is a time when inaccuracy prohibits their use. Where does one draw the line on accuracy when, for example, distributing local government grants? It's obvious to many local authorities that using current population estimates does not work for areas with large levels of migration and embedded ethnic communities. Doing so produces population decreases which don't add up when set against all other available data.